Basics of Undergraduate/university fellows
Complementation between two non-allelic genes (C and P) are essential for production
of a particular or special phenotype i.e., complementary factor.
Two genes involved in a specific pathway and their functional products are required
for gene expression, then one recessive allelic pair at either allelic pair would result in
the mutant phenotype.
When Dominant alleles are present together, they complement each other to yield
complementary factor resulting in a special phenotype.
They are called complementary genes.
When either of gene loci have homozygous recessive alleles (i.e., genotypes of ccPP,
ccPp, CCpp, Ccpp and ccpp), they produce identical phenotypes and change F2 ratio
to 9:7.
This document discusses different types of gene interactions including inter-allelic, intra-allelic, incomplete dominance, codominance, lethal genes, and multiple alleles. It provides examples of each type of interaction such as incomplete dominance in snapdragons resulting in pink flowers from white and red parents. Codominance is explained using ABO blood types where types A, B, and AB express both alleles. Lethal genes can be dominant or recessive and cause death in homozygous or heterozygous individuals. Multiple alleles are discussed in examples like the three alleles that determine ABO blood groups.
This power point presentation is designed to explain deviation of Mendelian dihybrid ratio due to interaction of genes which may be of following types
1.Two gene pairs affecting same character – 9:3:3:1
2.Epistasis, one gene hides effect of other
a) Recessive Epistasis - 9:3:4
b) Dominant epistasis - 12:3:1
3.Complementary genes - 9:7 ( 2 genes responsible for production of a particular phenotype )
4. Duplicate genes – 15:1 ( same effect given by either of two genes )
5. Polymeric gene action - 9:6:1
6. Inhibitory gene action - 13 : 3
Each interaction is typical in itself and ratios obtained are different
This document discusses gene interaction and different types of epistasis. It defines gene interaction as when the expression of one gene depends on the presence or absence of another gene. There are two main types of gene interaction - allelic/non-epistatic and non-allelic/epistatic. Epistasis refers to one gene masking or interfering with the expression of another gene. The document outlines and provides examples of different types of epistatic gene interactions, including dominant epistasis, recessive epistasis, dominant inhibitory epistasis, duplicate dominant epistasis, and duplicate recessive epistasis.
Basics of Undergraduate/university fellows
In supplementary gene action, the dominant allele of one gene is essential for the
development of the concerned phenotype, while the other gene modifies the expression of the first gene.
The document discusses various genetic concepts including gene interactions, dominance, codominance, incomplete dominance, lethal alleles, sex-influenced traits, penetrance, expressivity, environmental influences, pleiotropy, epistasis, and uses examples like flower color in plants and coat color in animals to illustrate these concepts. It explains that epistasis occurs when an allele of one gene masks the expression of alleles at another gene locus and defines different types of epistatic interactions like dominant epistasis and recessive epistasis.
This document discusses chromosome and gene mapping techniques. It describes how gene mapping is used to identify the location of genes and distances between genes on chromosomes. Two main types of maps are discussed - genetic maps based on linkage and physical maps using actual distances in base pairs. Molecular markers are described as polymorphic DNA sequences used to map genes. Methods for genetic mapping like linkage analysis and calculating recombination fractions are explained.
Gene interactions play an important role in inheritance and can produce phenotypes that do not follow typical Mendelian ratios. There are two main types of gene interactions - allelic and non-allelic. Allelic interactions occur between alleles of the same gene and can be complete dominance, incomplete dominance, or co-dominance. Non-allelic interactions occur between genes and can be simple interactions like those controlling comb patterns in chickens, or more complex interactions like epistasis where one gene suppresses the expression of another. Understanding gene interactions is crucial for explaining exceptions to Mendelian inheritance.
Basics of Undergraduate/university fellows
Complementation between two non-allelic genes (C and P) are essential for production
of a particular or special phenotype i.e., complementary factor.
Two genes involved in a specific pathway and their functional products are required
for gene expression, then one recessive allelic pair at either allelic pair would result in
the mutant phenotype.
When Dominant alleles are present together, they complement each other to yield
complementary factor resulting in a special phenotype.
They are called complementary genes.
When either of gene loci have homozygous recessive alleles (i.e., genotypes of ccPP,
ccPp, CCpp, Ccpp and ccpp), they produce identical phenotypes and change F2 ratio
to 9:7.
This document discusses different types of gene interactions including inter-allelic, intra-allelic, incomplete dominance, codominance, lethal genes, and multiple alleles. It provides examples of each type of interaction such as incomplete dominance in snapdragons resulting in pink flowers from white and red parents. Codominance is explained using ABO blood types where types A, B, and AB express both alleles. Lethal genes can be dominant or recessive and cause death in homozygous or heterozygous individuals. Multiple alleles are discussed in examples like the three alleles that determine ABO blood groups.
This power point presentation is designed to explain deviation of Mendelian dihybrid ratio due to interaction of genes which may be of following types
1.Two gene pairs affecting same character – 9:3:3:1
2.Epistasis, one gene hides effect of other
a) Recessive Epistasis - 9:3:4
b) Dominant epistasis - 12:3:1
3.Complementary genes - 9:7 ( 2 genes responsible for production of a particular phenotype )
4. Duplicate genes – 15:1 ( same effect given by either of two genes )
5. Polymeric gene action - 9:6:1
6. Inhibitory gene action - 13 : 3
Each interaction is typical in itself and ratios obtained are different
This document discusses gene interaction and different types of epistasis. It defines gene interaction as when the expression of one gene depends on the presence or absence of another gene. There are two main types of gene interaction - allelic/non-epistatic and non-allelic/epistatic. Epistasis refers to one gene masking or interfering with the expression of another gene. The document outlines and provides examples of different types of epistatic gene interactions, including dominant epistasis, recessive epistasis, dominant inhibitory epistasis, duplicate dominant epistasis, and duplicate recessive epistasis.
Basics of Undergraduate/university fellows
In supplementary gene action, the dominant allele of one gene is essential for the
development of the concerned phenotype, while the other gene modifies the expression of the first gene.
The document discusses various genetic concepts including gene interactions, dominance, codominance, incomplete dominance, lethal alleles, sex-influenced traits, penetrance, expressivity, environmental influences, pleiotropy, epistasis, and uses examples like flower color in plants and coat color in animals to illustrate these concepts. It explains that epistasis occurs when an allele of one gene masks the expression of alleles at another gene locus and defines different types of epistatic interactions like dominant epistasis and recessive epistasis.
This document discusses chromosome and gene mapping techniques. It describes how gene mapping is used to identify the location of genes and distances between genes on chromosomes. Two main types of maps are discussed - genetic maps based on linkage and physical maps using actual distances in base pairs. Molecular markers are described as polymorphic DNA sequences used to map genes. Methods for genetic mapping like linkage analysis and calculating recombination fractions are explained.
Gene interactions play an important role in inheritance and can produce phenotypes that do not follow typical Mendelian ratios. There are two main types of gene interactions - allelic and non-allelic. Allelic interactions occur between alleles of the same gene and can be complete dominance, incomplete dominance, or co-dominance. Non-allelic interactions occur between genes and can be simple interactions like those controlling comb patterns in chickens, or more complex interactions like epistasis where one gene suppresses the expression of another. Understanding gene interactions is crucial for explaining exceptions to Mendelian inheritance.
This document discusses balanced lethal systems in organisms. It provides examples of balanced lethal systems in Drosophila involving the curly and plum genes, and in Oenothera plants. In Oenothera, there are two types of balanced lethal mechanisms - one involving gametic lethality and the other involving zygotic lethality. The balanced lethal systems ensure that only heterozygotes survive by eliminating homozygotes for lethal alleles.
The concept of the gene has evolved over time based on experimental evidence:
1. Early views were that a gene equals one character (Mendel) or metabolic function (Garrod).
2. Experiments in the 1940s-50s showed genes encode enzymes or polypeptides.
3. Benzer's experiments in the 1950s-60s demonstrated that genes have fine structure and recombination can occur within genes, not just between genes. The nucleotide, not the gene, is the basic unit of genetic structure.
4. Complementation tests show a gene is the basic unit of function, though it can be divided into smaller functional units (cistrons). Alternative splicing further complicates the
Basics of Undergraduate/university fellows
Epistasis is a Greek word that means standing over.
BATESON used term epistasis to describe the masking effect in 1909
The term epistasis describes a certain relationship between genes, where an allele of
one gene hides or masks the visible output or phenotype of another gene.
When two different genes which are not alleles, both affect the same character in such
a way that the expression of one masks (inhibits or suppresses) the expression of the
other gene, the phenomenon is said to be epistasis.
The gene that suppresses other gene expression is known as Epistatic gene.
The gene that is suppressed or remain obscure is called Hypostatic gene
The classical phenotypic ratio of 9:3:3:1 F2 ratio becomes modified by epistasis.
Inheritance due to genes located in cytoplasm is called cytoplasmic inheritance.
Since genes governing traits showing cytoplasmic inheritance are located outside the nucleus and in the cytoplasm, they are referred to as plasmagenes.
This document discusses the structure and functions of chromosomes. It defines different types of chromosomes, such as monocentric and dicentric chromosomes. It describes chromomeres and homologous chromosomes. It discusses the physical structure of chromosomes including the centromere, secondary constriction, satellite, and telomere. It summarizes different chromosome models and explains functions of chromosomes like transmission of genetic material.
This document discusses several genetic patterns beyond Mendel's laws of inheritance, including incomplete dominance, codominance, multiple alleles, lethal alleles, sex-linked traits, cytoplasmic inheritance, genomic imprinting, anticipation, and environmental influences on traits. It provides examples for each pattern, such as pink flowers from incomplete dominance of red and white alleles or blood types from multiple alleles and codominance.
Sex Determnation and sex based inheritance(Genetic)Azida Affini
Sex determination refers to the natural process by which an individual becomes male or female. In humans and most mammals, sex is genetically determined at fertilization by the XY sex determination system, where females have two X chromosomes and males have one X and one Y chromosome. The SRY gene on the Y chromosome triggers testes development, making the individual male. In females without a Y chromosome, ovaries develop. To compensate for differences in X chromosome dosage between males and females, one of the two X chromosomes is randomly inactivated in females.
Lethal genes are genes that lead to the death of an organism. There are several types of lethal genes including early onset lethal genes that cause death during embryogenesis, late onset lethal genes that have delayed effects causing death over time, conditional lethal genes that only kill under certain environmental conditions, and semi-lethal genes that kill some but not all individuals. Some of the first observations of lethal genes included work in 1907 by E. Baur on snapdragon plants where homozygous aurea plants lacked chlorophyll and died, and work in 1905 by L. Cuenot on mouse coat color inheritance where yellow mice could not be obtained in homozygous condition.
This document provides an overview of Gregor Mendel's experiments with pea plants that laid the foundations for genetics. It discusses how Mendel studied seven traits in pea plants through controlled crosses between pure-breeding lines. His results demonstrated that traits are inherited as discrete units (now called genes or alleles) and showed dominance relationships. Mendel's work established the laws of segregation and independent assortment. Later researchers confirmed Mendel's findings through experiments with pea plants.
This document discusses genetic linkage and its related concepts and theories. It defines genetic linkage as the tendency of genes located near each other on the same chromosome to be inherited together. It describes Walter Sutton's hypothesis that chromosomes carry hereditary units and Sutton and Boveri's chromosome theory of inheritance. It also discusses Bateson and Punnett's coupling and repulsion hypothesis, Morgan's discovery of gene location on chromosomes through fly experiments, and the different types of linkage like complete and incomplete linkage. Examples are provided to illustrate concepts like complete and incomplete linkage.
Interaction of genes complimentary, supplementary and epistasisvaishalidandge3
This document discusses different types of gene interactions: complementary, supplementary, and epistasis. It provides examples for each type of interaction and explains how they modify typical Mendelian inheritance ratios. Complementary gene interaction requires two non-allelic genes (e.g. genes C and P in sweet pea) to produce a phenotype, leading to a 9:7 F2 ratio. Supplementary genes independently produce a phenotype but together modify the expression, seen as a 9:3:4 F2 ratio in maize grain color. Epistasis occurs when one gene suppresses another; this includes dominant, recessive, and inhibitory epistasis ratios of 12:3:1, 9:3:4, and
1. The document discusses mutation and its detection. It defines mutation as heritable changes in the genome excluding those from other organisms.
2. It describes different types of mutations such as spontaneous versus induced, forward versus reverse, nuclear versus cytoplasmic, and more.
3. Methods of detecting mutations in prokaryotes and eukaryotes are described. For prokaryotes, techniques like replica plating and the Ames test are used. For eukaryotes, each individual must be examined for mutant phenotypes.
Morgan conducted experiments in Drosophila melanogaster that discovered genetic linkage. He crossed a white-eyed, miniature-winged female to a wild-type male. In the F2 generation, most flies showed the parental phenotypes of white eyes and miniature wings, or wild-type eyes and wings. However, some flies showed non-parental phenotypes of white eyes and normal wings, or wild-type eyes and miniature wings, demonstrating genetic recombination between the two linked genes. This provided evidence that genes on the same chromosome may assort together during meiosis but can also undergo crossing over, resulting in new combinations of alleles. Morgan's discovery established the chromosomal theory of inheritance and allowed the field of genetics to construct genetic maps
This document discusses polygenic inheritance, which is when multiple genes cumulatively control a phenotypic trait, rather than a single gene following Mendelian ratios. It provides skin color in humans as an example of polygenic inheritance controlled by multiple genes. The document outlines the ratios expected from two or three controlling genes, and shows how skin color ranges from light to dark depending on the number of dominant alleles present, with the most dominant alleles resulting in darker skin.
The document discusses different types of epistatic interactions, including dominant and recessive epistasis where one gene hides the effects of another gene. It provides examples of different epistatic ratios seen in traits like eye color in Drosophila and fruit shape in plants. The types of epistasis covered include dominant, recessive, duplicate recessive genes, and genes with cumulative effects.
Biometrics is the science dealing with statistical analysis of biological problems. Quantitative genetics studies inheritance of quantitative traits using statistics. The two requirements for plant breeding are genetic variation and exploiting that variation through selection. Phenotype is influenced by both heritable (genetic) and non-heritable (environmental) factors. Quantitative traits are more influenced by environment and genetic background than qualitative traits. The relationship between genotype and phenotype for quantitative traits is partially hidden by environmental effects.
This document discusses gene interaction, which refers to how two or more genes can affect the expression of a single trait in an organism. It begins by defining gene interaction and explaining that many traits are governed by multiple genes rather than a single gene. The document then outlines different types of gene interactions, including epistatic and hypostatic interactions. It classifies epistatic gene interactions into several categories based on how the genes influence each other, such as supplementary, complementary, inhibitory, duplicate, masking, and polymeric gene interactions. Examples are provided for each category to illustrate how the interaction modifies the dihybrid or trihybrid ratios.
This document discusses multiple allelism, which refers to more than two alternative allelic forms of a gene occupying the same locus. It provides examples of multiple allelism in eye color in Drosophila, with 14 alleles producing different shades from white to red, and in human blood groups with the A, B, and O alleles. The characteristics of multiple alleles are described, including that only two alleles are present per individual. Multiple allelism in inheritance of blood groups and determining blood group combinations in offspring are also covered.
This document provides an overview of gene epistasis. It defines epistasis as the phenomenon where the effect of one gene is dependent on the presence of another gene. It discusses the different types of epistatic interactions, including dominant and recessive epistasis. As an example, it describes how epistasis influences human hair color through the interaction of genes that control production of eumelanin and pheomelanin. The document emphasizes that epistasis is important for understanding genetic pathways and evolutionary dynamics.
The document discusses several of Gregor Mendel's discoveries and laws of genetics from his experiments with pea plants including:
1) Mendel's law of segregation which states that alleles for a gene separate into gametes during reproduction.
2) His law of independent assortment which states that different genes assort independently if located on separate chromosomes.
3) That dominant alleles are fully expressed in heterozygotes while recessive alleles have no visible effect.
This document discusses balanced lethal systems in organisms. It provides examples of balanced lethal systems in Drosophila involving the curly and plum genes, and in Oenothera plants. In Oenothera, there are two types of balanced lethal mechanisms - one involving gametic lethality and the other involving zygotic lethality. The balanced lethal systems ensure that only heterozygotes survive by eliminating homozygotes for lethal alleles.
The concept of the gene has evolved over time based on experimental evidence:
1. Early views were that a gene equals one character (Mendel) or metabolic function (Garrod).
2. Experiments in the 1940s-50s showed genes encode enzymes or polypeptides.
3. Benzer's experiments in the 1950s-60s demonstrated that genes have fine structure and recombination can occur within genes, not just between genes. The nucleotide, not the gene, is the basic unit of genetic structure.
4. Complementation tests show a gene is the basic unit of function, though it can be divided into smaller functional units (cistrons). Alternative splicing further complicates the
Basics of Undergraduate/university fellows
Epistasis is a Greek word that means standing over.
BATESON used term epistasis to describe the masking effect in 1909
The term epistasis describes a certain relationship between genes, where an allele of
one gene hides or masks the visible output or phenotype of another gene.
When two different genes which are not alleles, both affect the same character in such
a way that the expression of one masks (inhibits or suppresses) the expression of the
other gene, the phenomenon is said to be epistasis.
The gene that suppresses other gene expression is known as Epistatic gene.
The gene that is suppressed or remain obscure is called Hypostatic gene
The classical phenotypic ratio of 9:3:3:1 F2 ratio becomes modified by epistasis.
Inheritance due to genes located in cytoplasm is called cytoplasmic inheritance.
Since genes governing traits showing cytoplasmic inheritance are located outside the nucleus and in the cytoplasm, they are referred to as plasmagenes.
This document discusses the structure and functions of chromosomes. It defines different types of chromosomes, such as monocentric and dicentric chromosomes. It describes chromomeres and homologous chromosomes. It discusses the physical structure of chromosomes including the centromere, secondary constriction, satellite, and telomere. It summarizes different chromosome models and explains functions of chromosomes like transmission of genetic material.
This document discusses several genetic patterns beyond Mendel's laws of inheritance, including incomplete dominance, codominance, multiple alleles, lethal alleles, sex-linked traits, cytoplasmic inheritance, genomic imprinting, anticipation, and environmental influences on traits. It provides examples for each pattern, such as pink flowers from incomplete dominance of red and white alleles or blood types from multiple alleles and codominance.
Sex Determnation and sex based inheritance(Genetic)Azida Affini
Sex determination refers to the natural process by which an individual becomes male or female. In humans and most mammals, sex is genetically determined at fertilization by the XY sex determination system, where females have two X chromosomes and males have one X and one Y chromosome. The SRY gene on the Y chromosome triggers testes development, making the individual male. In females without a Y chromosome, ovaries develop. To compensate for differences in X chromosome dosage between males and females, one of the two X chromosomes is randomly inactivated in females.
Lethal genes are genes that lead to the death of an organism. There are several types of lethal genes including early onset lethal genes that cause death during embryogenesis, late onset lethal genes that have delayed effects causing death over time, conditional lethal genes that only kill under certain environmental conditions, and semi-lethal genes that kill some but not all individuals. Some of the first observations of lethal genes included work in 1907 by E. Baur on snapdragon plants where homozygous aurea plants lacked chlorophyll and died, and work in 1905 by L. Cuenot on mouse coat color inheritance where yellow mice could not be obtained in homozygous condition.
This document provides an overview of Gregor Mendel's experiments with pea plants that laid the foundations for genetics. It discusses how Mendel studied seven traits in pea plants through controlled crosses between pure-breeding lines. His results demonstrated that traits are inherited as discrete units (now called genes or alleles) and showed dominance relationships. Mendel's work established the laws of segregation and independent assortment. Later researchers confirmed Mendel's findings through experiments with pea plants.
This document discusses genetic linkage and its related concepts and theories. It defines genetic linkage as the tendency of genes located near each other on the same chromosome to be inherited together. It describes Walter Sutton's hypothesis that chromosomes carry hereditary units and Sutton and Boveri's chromosome theory of inheritance. It also discusses Bateson and Punnett's coupling and repulsion hypothesis, Morgan's discovery of gene location on chromosomes through fly experiments, and the different types of linkage like complete and incomplete linkage. Examples are provided to illustrate concepts like complete and incomplete linkage.
Interaction of genes complimentary, supplementary and epistasisvaishalidandge3
This document discusses different types of gene interactions: complementary, supplementary, and epistasis. It provides examples for each type of interaction and explains how they modify typical Mendelian inheritance ratios. Complementary gene interaction requires two non-allelic genes (e.g. genes C and P in sweet pea) to produce a phenotype, leading to a 9:7 F2 ratio. Supplementary genes independently produce a phenotype but together modify the expression, seen as a 9:3:4 F2 ratio in maize grain color. Epistasis occurs when one gene suppresses another; this includes dominant, recessive, and inhibitory epistasis ratios of 12:3:1, 9:3:4, and
1. The document discusses mutation and its detection. It defines mutation as heritable changes in the genome excluding those from other organisms.
2. It describes different types of mutations such as spontaneous versus induced, forward versus reverse, nuclear versus cytoplasmic, and more.
3. Methods of detecting mutations in prokaryotes and eukaryotes are described. For prokaryotes, techniques like replica plating and the Ames test are used. For eukaryotes, each individual must be examined for mutant phenotypes.
Morgan conducted experiments in Drosophila melanogaster that discovered genetic linkage. He crossed a white-eyed, miniature-winged female to a wild-type male. In the F2 generation, most flies showed the parental phenotypes of white eyes and miniature wings, or wild-type eyes and wings. However, some flies showed non-parental phenotypes of white eyes and normal wings, or wild-type eyes and miniature wings, demonstrating genetic recombination between the two linked genes. This provided evidence that genes on the same chromosome may assort together during meiosis but can also undergo crossing over, resulting in new combinations of alleles. Morgan's discovery established the chromosomal theory of inheritance and allowed the field of genetics to construct genetic maps
This document discusses polygenic inheritance, which is when multiple genes cumulatively control a phenotypic trait, rather than a single gene following Mendelian ratios. It provides skin color in humans as an example of polygenic inheritance controlled by multiple genes. The document outlines the ratios expected from two or three controlling genes, and shows how skin color ranges from light to dark depending on the number of dominant alleles present, with the most dominant alleles resulting in darker skin.
The document discusses different types of epistatic interactions, including dominant and recessive epistasis where one gene hides the effects of another gene. It provides examples of different epistatic ratios seen in traits like eye color in Drosophila and fruit shape in plants. The types of epistasis covered include dominant, recessive, duplicate recessive genes, and genes with cumulative effects.
Biometrics is the science dealing with statistical analysis of biological problems. Quantitative genetics studies inheritance of quantitative traits using statistics. The two requirements for plant breeding are genetic variation and exploiting that variation through selection. Phenotype is influenced by both heritable (genetic) and non-heritable (environmental) factors. Quantitative traits are more influenced by environment and genetic background than qualitative traits. The relationship between genotype and phenotype for quantitative traits is partially hidden by environmental effects.
This document discusses gene interaction, which refers to how two or more genes can affect the expression of a single trait in an organism. It begins by defining gene interaction and explaining that many traits are governed by multiple genes rather than a single gene. The document then outlines different types of gene interactions, including epistatic and hypostatic interactions. It classifies epistatic gene interactions into several categories based on how the genes influence each other, such as supplementary, complementary, inhibitory, duplicate, masking, and polymeric gene interactions. Examples are provided for each category to illustrate how the interaction modifies the dihybrid or trihybrid ratios.
This document discusses multiple allelism, which refers to more than two alternative allelic forms of a gene occupying the same locus. It provides examples of multiple allelism in eye color in Drosophila, with 14 alleles producing different shades from white to red, and in human blood groups with the A, B, and O alleles. The characteristics of multiple alleles are described, including that only two alleles are present per individual. Multiple allelism in inheritance of blood groups and determining blood group combinations in offspring are also covered.
This document provides an overview of gene epistasis. It defines epistasis as the phenomenon where the effect of one gene is dependent on the presence of another gene. It discusses the different types of epistatic interactions, including dominant and recessive epistasis. As an example, it describes how epistasis influences human hair color through the interaction of genes that control production of eumelanin and pheomelanin. The document emphasizes that epistasis is important for understanding genetic pathways and evolutionary dynamics.
The document discusses several of Gregor Mendel's discoveries and laws of genetics from his experiments with pea plants including:
1) Mendel's law of segregation which states that alleles for a gene separate into gametes during reproduction.
2) His law of independent assortment which states that different genes assort independently if located on separate chromosomes.
3) That dominant alleles are fully expressed in heterozygotes while recessive alleles have no visible effect.
Gene action and modification of mendelianBruno Mmassy
This document discusses several types of gene action and inheritance patterns, including complete dominance, incomplete dominance, codominance, overdominance, gene interactions, epistasis, pleiotropy, sex-linked genes, penetrance, and essential genes. It provides examples for each type, such as ABO blood groups showing codominance and coat color in mice demonstrating epistasis.
Gene interaction -Complementary, Supplementary,Dominant Epistasis, Recessive...Nethravathi Siri
Most of the characters of living organisms are controlled/ influenced/ governed by a collaboration of several different genes. • Numerous deviations have been recorded in which different kinds of interactions are possible between the genes.
The document discusses various types of gene interactions that result in inheritance patterns other than simple Mendelian ratios. It describes allelic gene interactions including incomplete dominance, codominance, and lethal factors. It also describes non-allelic gene interactions such as simple interaction, complementary factors, epistasis, inhibitory factors, and polymeric/duplicate genes. The interactions can result from multiple alleles, modifying genes, suppressor genes, pleiotropy, atavism, variable penetrance, and expressivity of traits.
ppt on the modificationn_of_mendelian_ratio.pptxMonchLaceda
This document discusses various ways that alleles can alter phenotypes and modify Mendelian ratios. It describes different types of mutations that can cause loss or gain of function. It also explains genetic symbols used to represent alleles and different inheritance patterns such as incomplete dominance, codominance, lethal alleles, and epistasis. Multiple examples are provided to illustrate these concepts, such as coat color in mice, fruit color in squash, and flower color in peas. The key point is that while principles of segregation and independent assortment still hold, gene interactions can produce novel phenotypes and modified dihybrid ratios expressed in sixteenths.
Gene interactions occur when the expression of one gene depends on the presence or absence of another gene. There are several types of non-additive gene interactions:
1. Dominance - one allele masks the other (e.g. complete, incomplete, overdominance)
2. Epistasis - genes at different loci interact so one gene masks the other (e.g. supplementary, complementary, inhibitory, duplicate, masking)
3. Examples include flower color in sweet peas (complementary), anthocyanin in rice (inhibitory), and fruit shape in summer squash (polymeric).
This PowerPoint presentation intends to explore the thought and development of genetics after G.J.Mendel along with the factor hypothesis in this new line of research during the contemporary.
This document discusses different types of gene interactions:
1. Allelic interactions involve alleles of the same gene and can result in incomplete dominance or co-dominance.
2. Non-allelic interactions involve two or more genes affecting the same trait. Examples include epistasis where one gene masks the expression of another, and complementary genes where both are required for expression.
3. Gene interactions can modify Mendelian ratios and result in traits governed by multiple genes interacting in complex ways. The document provides examples for many gene interaction principles.
The document summarizes Gregor Mendel's experiments with pea plants that established the fundamental principles of heredity and genetics. Through breeding and tracking inherited traits in pea plants over multiple generations, Mendel discovered that traits are passed from parents to offspring through discrete units (genes) that segregate and assort independently. Mendel's work formed the basis of classical genetics and established the laws of segregation and independent assortment.
This document discusses apparent deviations from Mendel's laws of inheritance. It describes several genetic phenomena that can produce inheritance patterns different from classic Mendelian ratios, including polymery, complementary genes, epistasis, cryptomery, and gene interactions. Polymery involves multiple alleles at a single gene locus influencing a trait. Complementary genes require two dominant alleles together to express a phenotype. Epistasis occurs when one dominant gene masks the expression of another. Cryptomery means a trait is only expressed when two normally hidden dominant genes are present simultaneously. Gene interactions were demonstrated through experiments on chicken comb phenotypes.
This document summarizes key concepts relating to extensions of Mendelian principles in genetics. It discusses topics like multiple alleles, modifications of dominance relationships, gene interactions, essential genes and lethal alleles, the influence of environment on gene expression, and epigenetics. For example, it explains that multiple alleles of a gene can result in more than two phenotypes, dominance relationships can be complete, incomplete, or codominant, and gene interactions and environment can modify expected Mendelian ratios.
This document discusses different types of gene interactions including dominance, incomplete dominance, codominance, epistasis, duplicate gene action, alternate epistasis, and lethality. Gene interactions can result in novel phenotypes that differ from the individual gene effects. Lethal genes cause death and can be dominant or recessive, with recessive lethal genes resulting in a phenotypic ratio change from 3:1 to 2:1. Examples of human recessive lethal conditions include congenital ichthyosis and Cooley's anemia.
This document discusses different types of gene interactions:
1. Hereditary traits like eye color are passed from parents to offspring, while non-hereditary traits like scars are acquired during one's lifetime.
2. Examples of gene interactions include recessive epistasis in mice coat color and dominant epistasis in squash fruit color. In recessive epistasis, a recessive allele masks other alleles, while in dominant epistasis a dominant allele masks other alleles.
3. Other types of gene interactions discussed include dominant inhibitory epistasis shown in rice pigmentation, duplicate recessive epistasis in pea flower color, and polymeric gene interaction in squash fruit shape inheritance. Each interaction results
Mendel discovered three laws of inheritance through experiments breeding pea plants:
1) The Law of Segregation states that alleles for a gene separate during gamete formation such that each gamete carries one allele.
2) The Law of Dominance describes how some alleles are dominant and others recessive, with dominant alleles determining the phenotype.
3) The Law of Independent Assortment explains that genes assort independently of one another during gamete formation, resulting in a 9:3:3:1 phenotypic ratio for two gene traits.
Biology 103 Laboratory Exercise – Genetic Problems
Introduction
Although the science of genetics has become a highly sophisticated discipline dealing
with the interactions of hereditary factors at the molecular level, it has its roots in the
basic laws of heredity initially discovered and presented by Gregor Mendel more than
one hundred years ago. Mendel's success in discovering these laws was due largely to his
application of the simple rules of mathematical probability - the laws of chance - to his
observations concerning the inheritance of certain characteristics in the garden pea plant.
Reginald Punnett and the Punnett Square
The Punnett square is a diagram used by biologists to determine genotypic probability
within the offspring from a particular genetic cross. The Punnett square shows every
possible genotypic combination of maternal alleles with the paternal alleles for a genetic
cross. Punnett squares only give probabilities for genotypes, not phenotypes. The square
diagram was designed by the British geneticist, Reginald Punnett (1865-1967) and first
presented to the science community in 1905. Punnett’s Mendelism (1905) is considered
the first popular science book to introduce genetics to the public.
Solving Genetic Problems
R
R'
R
RR RR'
R'
RR' R'R'
Maternal alleles
A
A
a
Aa
Aa
Paternal
Alleles
a
Aa
Aa
The first step in solving a genetic problem is to establish the genetic symbols you will use
in your problem solution. Stay consistent by using these same symbols throughout the
problem solving process.
Represent dominant and recessive alleles (different forms of a gene) using traditional
genetic symbols. Dominant alleles should be represented with the capital version of an
alphabetic letter while using the lower case version to show recessiveness. For example:
B = black color, b = white color.
Each individual gene or trait is diploid (2n) in nature and therefore, must be represented
with two alleles. Continuing with the alleles mentioned previously, an individual may
have the genetic makeup BB, Bb, or bb when using those alleles.
Remember that gametes (sperm and egg) are haploid (n) and can only provide one allele
per trait. For example: B or b
An individual’s genotype contains the possible gametes that can be expected to be
produced by that individual. Much of genetics revolves around the probability of the
makeup of gametes. If the individual is homozygous, all of the gametes produced will
possess the same kind of allele. For example, an individual with the genotype BB would
be expected to produce only B gametes and individuals with genotype bb would produce
only b gametes.
If the individual is heterozygous, that is the individual’s genotype contains one dominant
allele and one recessive allele (Bb), the gametes produced will possess one or the other of
the two forms of the gene – B or b. ...
This document discusses exceptions to Mendel's laws of inheritance. It begins by outlining Mendel's original laws and concepts of genes and inheritance. It then notes that not all traits follow Mendel's predictions. There are two types of exceptions: 1) where genotypic ratios follow Mendel but phenotypes do not, and 2) where both genotypes and phenotypes deviate. Specific exceptions covered include incomplete dominance, codominance, polygenic inheritance, multiple alleles, lethal genes, and sex-linked inheritance. Real-world examples are provided for each exception.
The document discusses basic genetics concepts including:
- Gregor Mendel studied heredity through pea plant experiments in the 1800s.
- Mendel observed that traits separated and recombined when parent plants differing in one trait were crossed.
- Terms like dominant, recessive, genotype and phenotype were introduced to explain his findings.
- The Punnett square was developed as a tool to predict potential offspring of crosses.
- Genetics is the study of heredity and traits being passed from parents to offspring through genes.
- Gregor Mendel conducted experiments with pea plants to study inheritance, observing that traits can be dominant or recessive.
- Through his experiments, Mendel determined that individuals have two alleles for each trait, and that for recessive traits to be expressed, an individual must be homozygous for the recessive allele.
This PPT consists of 24 slides explaining Polygenic Inheritance . Some traits are controlled by two or more genes. These traits differ from Mendelian traits and donot show discrete alternative or contrasting forms and show continuous ranges. Examples of such traits are wheat seed colour, plant height, Human skin colour controlled by at least three genes showing many shades of dark and fare, human height, human eye colour etc
Mechanisms and Applications of Antiviral Neutralizing Antibodies - Creative B...Creative-Biolabs
Neutralizing antibodies, pivotal in immune defense, specifically bind and inhibit viral pathogens, thereby playing a crucial role in protecting against and mitigating infectious diseases. In this slide, we will introduce what antibodies and neutralizing antibodies are, the production and regulation of neutralizing antibodies, their mechanisms of action, classification and applications, as well as the challenges they face.
PPT on Alternate Wetting and Drying presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
BIRDS DIVERSITY OF SOOTEA BISWANATH ASSAM.ppt.pptxgoluk9330
Ahota Beel, nestled in Sootea Biswanath Assam , is celebrated for its extraordinary diversity of bird species. This wetland sanctuary supports a myriad of avian residents and migrants alike. Visitors can admire the elegant flights of migratory species such as the Northern Pintail and Eurasian Wigeon, alongside resident birds including the Asian Openbill and Pheasant-tailed Jacana. With its tranquil scenery and varied habitats, Ahota Beel offers a perfect haven for birdwatchers to appreciate and study the vibrant birdlife that thrives in this natural refuge.
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Embracing Deep Variability For Reproducibility and Replicability
Abstract: Reproducibility (aka determinism in some cases) constitutes a fundamental aspect in various fields of computer science, such as floating-point computations in numerical analysis and simulation, concurrency models in parallelism, reproducible builds for third parties integration and packaging, and containerization for execution environments. These concepts, while pervasive across diverse concerns, often exhibit intricate inter-dependencies, making it challenging to achieve a comprehensive understanding. In this short and vision paper we delve into the application of software engineering techniques, specifically variability management, to systematically identify and explicit points of variability that may give rise to reproducibility issues (eg language, libraries, compiler, virtual machine, OS, environment variables, etc). The primary objectives are: i) gaining insights into the variability layers and their possible interactions, ii) capturing and documenting configurations for the sake of reproducibility, and iii) exploring diverse configurations to replicate, and hence validate and ensure the robustness of results. By adopting these methodologies, we aim to address the complexities associated with reproducibility and replicability in modern software systems and environments, facilitating a more comprehensive and nuanced perspective on these critical aspects.
https://hal.science/hal-04582287
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdf
Gene interactions
1.
2. Complementary Genes:
They are those non-allelic genes which independently show a similar effect but produce a new trait when
present together in the dominant form.
Complementary genes were first studied by Bateson and Punnet (1906) in case of flower colour of Sweet Pea
(Lathyrus odoratus).
The latter is also an example of recessive epistasis where the recessive homozygous alleles of one type suppress the effect
of dominant alleles of the other type. Here, the flower colour is purple if dominant alleles of two genes are present
together (С—P—). The colour is white if the double dominant condition is absent (ccP—, С—pp, ccpp).
3. Bateson and Punnet (1906) crossed two white flowered strains (CCpp, ccPP) of Sweet Pea and obtained
purple flowered plants (CcPp) in the F1 generation.
Clearly both the parents have contributed a gene or factor for the synthesis of this purple colour. The
purple flowered plants of F1 generation were then allowed to self-breed.
Both purple and white flowered plants appear in the F2 generation in the ratio of 9: 7.
It is a modification of the di-hybrid ratio of 9: 3: 3: 1. The appearance of purple colour in 9/16 population
shows that the colour is determined by two dominant genes (C and P). When either of the two is absent
(ccPP or CCpp, ccPp or Ccpp), the pigment does not appear
4. Supplementary Genes:
Supplementary genes are a pair of non-allelic genes, one of which produces its effect
independently in the dominant state while the dominant allele of the second gene (supplemen-
tary gene) needs the presence of other gene for its expression.
Supplementary Genes in Lablab:
Lablab has two genes, K and L. In the recessive state the second or supplementary gene (11) has no effect on seed
coat colour.
Dominant К independently produces Khaki colour while its recessive allele gives rise to buff colour irrespective of
the supplementary gene being dominant or recessive. In the dominant state the supplementary gene (L—)
changes the effect of dominant allele of pigment forming gene (K) into chocolate colour. F2 ratio is 9: 3: 4
5. Modified Supplementary Genes/Collaborative Supplementary
Genes/Collaboration:
They are two nonallelic genes which not only are able to produce their own effects independently when
present in the dominant state but can also interact to form a new trait. Comb types in poultry is an example
of collaborative supplementary genes, P and R.
When none of these genes is present in the dominant state (pprr), single comb is formed.
In case P alone is dominant, a pea comb is formed (Pprr, PPrr). If R alone is dominant, a rose comb is
obtained (ppRr, ppRR). A walnut comb is formed when both P and R occur together in dominant state ( P — R
—) to produce supplementary effect.
When pure pea combed and pure rose combed birds are crossed, all the offspring of F, individuals have walnut
comb. On inbreeding the walnut combed birds, the F2 generation comes to have all the four types of combs in
the ratio of 9 walnut: 3 pea: 3 rose: 1 single
6.
7. What is Polygenic Inheritance?
Polygenic inheritance
Many traits and phenotypic characters present in plants and animals such as height, skin pigmentation,
hair and eye colour, milk and egg production are inherited through many alleles present in different loci.
This is known as polygenic inheritance.
If we take an example of height or skin pigmentation in humans, we find many different forms of the two traits.
We can’t categorise people in just two categories like ‘tall’ and ‘short’ for height or ‘dark’ and ‘light’ for the skin
colour.
We find continuous variation for both these traits because these traits are controlled by multiple genes. There
are as many as 400 genes that control the trait of height and are responsible for variation in height present in
the population.
Polygenic Inheritance Definition
Polygenic inheritance is defined as quantitative inheritance, where multiple independent genes have an
additive or similar effect on a single quantitative trait. Polygenic inheritance is also known as multiple gene
inheritance or multiple factor inheritance.
8. Polygenic Inheritance Examples
Polygenic Inheritance in Humans
There are many traits in humans, which show polygenic inheritance, e.g. skin and hair colour, height, eye colour, the
risk for diseases and resistance, intelligence, blood pressure, bipolar disorder, autism, longevity, etc.
Brief description of some of the traits:
1.Skin pigmentation: inheritance of skin pigmentation is polygenic inheritance. Around 60 loci contribute to the
inheritance of a single trait.
1. If we take an example of a pair of alleles of three different and unlinked loci as A and a, B and b, C and c. The
capital letters represent the incompletely dominant allele for dark skin colour.
2.The more capital letters show skin colour towards the darker range and small letters towards the lighter colour of the
skin. Parents having genotype AABBCC and aabbcc will produce offsprings of intermediate colour in the F1 generation,
i.e. AaBbCc genotype.
3. In the F2 generation of two triple heterozygotes (AaBbCc x AaBbCc) mate, they will give rise to varying phenotypes
ranging from very dark to very light in the ratio 1:6:15:20:15:6:1.
9. Punnett square showing F2 generation offsprings continuous variation
From light to dark→
1.Height: There are around 400 genes responsible for the phenotype and environment greatly influences the
expression of genes.
2.Eye colour: The colour of the eye is determined by polygenes. At least 9 colours of eye colour are
recognised in humans. There are two major eye colour genes and 14 more genes that determine the
expression of the phenotype. A different number of alleles contribute to each colour. These are found to be X-
linked.
Skin pigmentation
10. Duplicate Gene
Sometimes a character is controlled by two non-allelic genes whose dominant alleles produce the same
phenotype whether they are alone or together.
In Shepherd’s purse (Capsella bursa-pastoris), the presence of either gene A or gene B or both results in
triangular capsules; when both these genes are in recessive forms, the oval capsules produced
11. Duplicate Gene with Dominance Modification
(11:5):
A character controlled by two gene pairs showing dominance only if two dominant alleles are present. Dominant
phenotype will thus be produced only when two non-allelic dominant alleles or two allelic dominant alleles are
present. Such a case is found in pigment glands of cotton