Lethal Gene.pptx
•Download as PPTX, PDF•
0 likes•61 views
Lethal genes are genes that cause death or reduced viability in individuals carrying them. Some lethal genes cause death early in development like at the zygote or embryonic stage, while others act later in development. There are three main types of lethal genes: recessive lethals, which only cause death when homozygous; dominant lethals, which reduce viability even in heterozygotes; and conditional lethals, which require a specific condition like temperature to express their lethal effects. One of the first lethal genes discovered was the Y gene in mice, which causes death when homozygous (YY) but not when heterozygous (Yy).
Report
Share
Report
Share
Recommended
Lethal genes
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.
definition of gene,allele,types of gene,structure of gene and heredity charac...
This document discusses different types of genes including: complementary genes, duplicate genes, polymeric genes, modifying genes, and lethal genes. It provides examples of each gene type and how they interact to influence inheritance and traits. Complementary genes require two genes to work together to produce a trait. Duplicate genes have the same effect on a trait. Polymeric genes have an additive effect. Modifying genes influence other genes. Lethal genes cause death and can be dominant, recessive, sex-linked, or conditional.
environmental influence on gene expression
This document discusses how environmental factors can influence gene expression. It provides examples of how temperature, light, chemicals, and nutrition can all impact the expression of genes in rabbits, maize plants, fish embryos, and humans. The document also covers different types of lethal alleles, including recessive, dominant, conditional, sex-linked, and conditional lethal alleles. Recessive lethal alleles do not cause death unless an organism carries two copies, while dominant lethal alleles are expressed in both homozygotes and heterozygotes. Conditional lethal alleles only cause death when certain environmental changes are introduced. Sex-linked lethal alleles are carried on the X chromosome.
MUTATIONS FINAL.kinds of mutation,causes
Mutations are inheritable changes in genetic material that can occur due to errors during DNA replication or exposure to mutagens. There are several types of mutations classified based on factors such as the cells they occur in, the chromosomes affected, their mode of origin, phenotypic effects, and more. Examples of different mutation types provided in the document include lethal mutations like Huntington's disease, conditional mutations seen in Siamese cat fur color, and specific point mutations responsible for conditions like sickle cell anemia. Ploidy changes, chromosomal aberrations, gene mutations, and frameshift mutations all involve genetic alterations that can result in disease.
Plant Cytogenetics: Inheritance of Lethal genes.
Prepared for B. Sc. III Botany students, based on the syllabus prescribed by Dr. Babasaheb Ambedkar Marathwada University, Aurangabad.
Genetic Interaction and Lethal Gene.pptx
This document discusses several genetic concepts including epistatic interactions, atavism or reversion, lethal genes, penetrance, expressivity, and pleiotropism. It provides examples for each concept to illustrate how they occur and influence phenotypic expression. Epistatic interactions can result in less than four phenotypes in a dihybrid cross. Atavism is when an F1 offspring resembles a more remote ancestor rather than its immediate parents. Lethal genes can cause death at different developmental stages or modify phenotypic ratios. Penetrance and expressivity describe how fully and variably a genotype is expressed, which can be influenced by environment. Pleiotropic genes have multiple phenotypic effects.
Balanced Lethals and Chromosome Complexes
This document discusses balanced and unbalanced lethal genes. It provides the example of the yellow mouse, which is lethal when homozygous for the yellow gene due to failure of yellow sperm to penetrate yellow eggs. It then describes balanced lethal systems, where two different recessive lethal genes balance each other's effects to allow survival of heterozygotes. Muller's discovery of the balanced lethal genes beaded and Le in Drosophila is described. The document also discusses chromosome complexes in Oenothera lamarckiana, where the alpha and beta gametic complexes lead to gametic lethality, while complexes gaudens and velans show zygotic lethality.
Beyond Mendel's laws of Inheritance.pdfa
This document discusses several concepts that extend beyond Mendel's laws of inheritance:
- Incomplete dominance occurs when neither allele of a gene is fully dominant, resulting in an intermediate phenotype in heterozygotes. Examples given include flower color in plants and cholesterol levels in humans.
- Multiple alleles exist when a gene has more than two alleles in a population. The ABO blood group in humans, which has A, B, and O alleles, is provided as an example.
- Sex-linked traits involve genes located on the X or Y chromosome, rather than autosomal chromosomes. Examples of X-linked traits that mainly affect males like hemophilia and Duchenne muscular dystrophy are described.
Recommended
Lethal genes
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.
definition of gene,allele,types of gene,structure of gene and heredity charac...
This document discusses different types of genes including: complementary genes, duplicate genes, polymeric genes, modifying genes, and lethal genes. It provides examples of each gene type and how they interact to influence inheritance and traits. Complementary genes require two genes to work together to produce a trait. Duplicate genes have the same effect on a trait. Polymeric genes have an additive effect. Modifying genes influence other genes. Lethal genes cause death and can be dominant, recessive, sex-linked, or conditional.
environmental influence on gene expression
This document discusses how environmental factors can influence gene expression. It provides examples of how temperature, light, chemicals, and nutrition can all impact the expression of genes in rabbits, maize plants, fish embryos, and humans. The document also covers different types of lethal alleles, including recessive, dominant, conditional, sex-linked, and conditional lethal alleles. Recessive lethal alleles do not cause death unless an organism carries two copies, while dominant lethal alleles are expressed in both homozygotes and heterozygotes. Conditional lethal alleles only cause death when certain environmental changes are introduced. Sex-linked lethal alleles are carried on the X chromosome.
MUTATIONS FINAL.kinds of mutation,causes
Mutations are inheritable changes in genetic material that can occur due to errors during DNA replication or exposure to mutagens. There are several types of mutations classified based on factors such as the cells they occur in, the chromosomes affected, their mode of origin, phenotypic effects, and more. Examples of different mutation types provided in the document include lethal mutations like Huntington's disease, conditional mutations seen in Siamese cat fur color, and specific point mutations responsible for conditions like sickle cell anemia. Ploidy changes, chromosomal aberrations, gene mutations, and frameshift mutations all involve genetic alterations that can result in disease.
Plant Cytogenetics: Inheritance of Lethal genes.
Prepared for B. Sc. III Botany students, based on the syllabus prescribed by Dr. Babasaheb Ambedkar Marathwada University, Aurangabad.
Genetic Interaction and Lethal Gene.pptx
This document discusses several genetic concepts including epistatic interactions, atavism or reversion, lethal genes, penetrance, expressivity, and pleiotropism. It provides examples for each concept to illustrate how they occur and influence phenotypic expression. Epistatic interactions can result in less than four phenotypes in a dihybrid cross. Atavism is when an F1 offspring resembles a more remote ancestor rather than its immediate parents. Lethal genes can cause death at different developmental stages or modify phenotypic ratios. Penetrance and expressivity describe how fully and variably a genotype is expressed, which can be influenced by environment. Pleiotropic genes have multiple phenotypic effects.
Balanced Lethals and Chromosome Complexes
This document discusses balanced and unbalanced lethal genes. It provides the example of the yellow mouse, which is lethal when homozygous for the yellow gene due to failure of yellow sperm to penetrate yellow eggs. It then describes balanced lethal systems, where two different recessive lethal genes balance each other's effects to allow survival of heterozygotes. Muller's discovery of the balanced lethal genes beaded and Le in Drosophila is described. The document also discusses chromosome complexes in Oenothera lamarckiana, where the alpha and beta gametic complexes lead to gametic lethality, while complexes gaudens and velans show zygotic lethality.
Beyond Mendel's laws of Inheritance.pdfa
This document discusses several concepts that extend beyond Mendel's laws of inheritance:
- Incomplete dominance occurs when neither allele of a gene is fully dominant, resulting in an intermediate phenotype in heterozygotes. Examples given include flower color in plants and cholesterol levels in humans.
- Multiple alleles exist when a gene has more than two alleles in a population. The ABO blood group in humans, which has A, B, and O alleles, is provided as an example.
- Sex-linked traits involve genes located on the X or Y chromosome, rather than autosomal chromosomes. Examples of X-linked traits that mainly affect males like hemophilia and Duchenne muscular dystrophy are described.
Complete Genetics
This document provides an overview of genetics concepts including classical genetics, molecular genetics, and evolutionary genetics. It discusses Mendel's laws of inheritance including dominance, segregation, and independent assortment. It defines key genetics terms like genotype, phenotype, homozygous, heterozygous, alleles, and genes. It also covers exceptions to Mendel's laws including incomplete dominance, codominance, and lethal alleles. Finally, it discusses linkage and crossing over between genes located on the same chromosome.
Lethal genes and gene therapy
This document provides information about lethal genes and gene therapy. It defines lethal genes as genes that reduce viability or cause death. It describes different types of lethal alleles such as early onset, late onset, conditional, and semi-lethal. Examples of dominant and recessive lethal genes are discussed, including diseases like Huntington's disease and conditions in mice coat color. Gene therapy is introduced as a way to insert normal genes to treat diseases caused by defective genes. The two main approaches of gene therapy - ex vivo and in vivo - are outlined. Viral and non-viral vectors used to deliver genes are also summarized.
Post-Mendelian Genetics
This presentation offers an interaction about Post-Mendelian genetics overview with special refrence4 to Mono-hybrid interaction.
Mendelian genetics
This document provides definitions and explanations of key concepts in Mendelian genetics. It discusses Mendel's laws of segregation, independent assortment, and dominance. It also summarizes exceptions to Mendelian ratios, including lethal alleles, incomplete dominance, codominance, and other factors like epistasis, pleiotropy, genetic heterogeneity, variable expressivity, and incomplete penetrance.
lethal genes
1. Lethal genes are genes that cause death or reduced viability when carried by an individual. They can be dominant or recessive.
2. Some examples of lethal genes discussed are Huntington's disease, cystic fibrosis, sickle cell anemia, and coat color genes in mice.
3. Gene therapy aims to treat diseases caused by defective genes by inserting functional genes. It can target somatic or germ-line cells. Viral and non-viral vectors are used to deliver therapeutic genes.
Genetic
This document discusses human genetics and genetic disorders. It begins by noting statistics on genetic abnormalities in newborns and diseases with a genetic component. It then defines genetics, genomics, proteomics, and single nucleotide polymorphisms. The rest of the document discusses molecular bases of human disease including functional and positional cloning. It classifies human diseases and discusses mutations, Mendelian disorders, X-linked disorders, and autosomal dominant and recessive patterns of inheritance. Key points covered include definitions of genetic terms, Mendel's laws of inheritance, mechanisms of various disorders, and inheritance patterns.
GENETIC DISORDER IN LIVESTOCK ANIMAL
Genetic disorders can occur in livestock animals due to mutations in genes or chromosomal abnormalities. In cattle, common genetic disorders include dwarfism, osteopetrosis (marble bone disease), tibia hemimelia, and pulmonary hypoplasia with anasarca. Sheep disorders include spider lamb syndrome and rectal prolapse. Chicken disorders include bent toes and split wings. Goats can experience epidermolysis bullosa or the fainting goat condition. Prevention of genetic disorders in livestock is important for economic reasons and involves selective breeding practices like culling affected animals and avoiding inbreeding to reduce homozygosity.
Balanced lethal system
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.
Molecular basis of genetic disease
Brief description on mendelian and non mendelian inheritance for undergraduate and post graduate learning
10. patterns of inheritance
Gregor Mendel's pea plant experiments in the mid-19th century laid the groundwork for genetics by demonstrating that traits are passed from parents to offspring via discrete units of inheritance called genes. The document defines genetic terminology like alleles, genotypes, phenotypes, dominant/recessive traits, and describes Mendel's laws of segregation and independent assortment. It also discusses sex-linked inheritance and variations like incomplete dominance and polygenic traits. Common human genetic disorders are reviewed including examples like sickle cell disease, cystic fibrosis, and Duchenne muscular dystrophy.
16. Lecture 16 Lethel genes, pleiotropy.ppt
The document discusses several genetics concepts:
1. Lethal genes can cause death before or after birth if both alleles are present, as seen in creeper chickens where the expected 3:1 ratio is instead 2:1.
2. Pleiotropy occurs when a single gene influences multiple traits, like sickle-cell anemia affecting hemoglobin and health.
3. Penetrance refers to the proportion of individuals that exhibit phenotypic effects of a gene, which can be complete or incomplete. Expressivity is the degree of phenotypic expression.
4. Multiple alleles exist at a single locus, like the four fur colors in rabbits controlled by Agouti, Chinchilla, Himalayan, and Al
Which statement describes a similarity between the diploid and haplo.pdf
Which statement describes a similarity between the diploid and haploid phases of plant life?
A zygote is formed ____.
Human skin color is an example of ____, while sickle-cell anemia is an example of ____.both
are multicellular
Solution
1. both are multicellular.
The plant life cycle alternates between haploid and diploid generations.Plants have multicellular
haploid and multicellular diploid stages in their life cycle.Gametes develop in the multicellular
haploid gametophyte.Fertilization gives rise to a multicellular diploid sporophyte,which
produces haploid spores via meiosis.
2.Zygote is formed by the fusion of egg and sperm nuclei.
In human fertilization,ovum which is a haploid secondary oocyte and a haploid sperm cell
combine to form a single 2n diploid cell called the zygote.
In fungi,the sexual fusion of haploid cells is called karyogamy.This cell may then enter meiosis
or mitosis depending on the life cycle of the species.
In plants,the zygote may be polyploid if fertilization occurs between meiotically unreduced
gametes.
Somatic cells are other than reproductive cells.Zygote formation occurs in reproductive cells.
3.Human skin color is an example of polygenic inheritance, while sickle-cell anemia is an
example of pleiotropy.
Polygenic inheritance occurs when one characteristic is controlled by two or more genes.Skin
color is largely determined by the amount of melanin. Dark skinned individuals produce more
melanin than light skinned individuals.At least three genes regulate the amount of melanin
produced. Each gene has two forms: dark skin allele (A,B,and C) and light skin allele (a,b,and c).
Pleiotropy occurs when variation at a single gene locus affects multiple aspects of the
phenotype.Sickle cell anemia is a genetic disease that causes deformed red blood cells with a
rigid,crescent shape instead of the normal flexible,round shape.It is caused by a change in one
nucleotide in the HBB gene.Sickle cell anemia occurs when the HBB gene mutation causes both
beta-globin subunits of hemoglobin to change into hemoglobin S..
ppt on the modificationn_of_mendelian_ratio.pptx
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 interaction ppt
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.
Lethal allele
This document discusses lethal alleles, which are alleles that cause death in an organism. It defines lethal alleles and provides a brief history of their discovery through early studies of coat color inheritance in mice. The document outlines four types of lethal alleles: early onset alleles that cause death early in life, late onset alleles that cause death late in life, conditional alleles that only cause death under certain environmental conditions, and semi-lethal alleles that only kill some individuals, not all. It provides the example of the Y gene in mice, which causes a yellow coat color but is lethal when present in the homozygous dominant state (YY), though not in the heterozygous or recessive states.
Gene Defects
1) Gene mutations and chromosomal abnormalities can cause a variety of genetic disorders and diseases.
2) A single base pair change in DNA can cause mutations like sickle cell anemia, while errors in meiosis can result in aneuploidies including extra or missing chromosomes.
3) Examples of genetic disorders include Tay-Sachs disease, cystic fibrosis, Huntington's disease, and Down syndrome which is caused by trisomy 21. These disorders alter genes and result in physical or mental impairments.
TRADITIONAL INHERITANCE
The modern scientific era begins with the work of Austrian monk, Gregor Mendel, who in 1865 presented the results of his breeding experiments on contrasting characters in garden peas
Mendel's laws of inheritance
Dominant inheritance
Dominant mutations are expressed when only one copy of that mutation is present. Therefore, anyone who inherits one dominant disease mutation such as the mutation for Huntington’s disease will have that disease.
Dominantly inherited genetic diseases tend to occur in every generation of a family. Each affected person usually has one affected parent.
However, dominant mutations can also happen in an individual for the first time, with no family history of the condition (spontaneous mutation).
Patterns of Inheritance
This document discusses several patterns of inheritance including:
1. Dominant and recessive genes and how they determine traits like coat color in mice.
2. Lethal alleles that cause death in homozygous dominant genotypes.
3. Incomplete dominance and codominance where both alleles are partially or fully expressed.
4. Sex linkage and how traits on the X chromosome are inherited differently between males and females.
It also discusses environmental influences on gene expression and abnormal chromosome numbers leading to conditions like Down syndrome.
Lecture 27 - Polyploidy breeding.ppt
This document discusses polyploidy in plant breeding. It defines key terms like diploidy, polyploidy, haploidy, and aneuploidy. It describes different types of polyploids like autopolyploids which have identical genomes, and allopolyploids which have distinct genomes. Methods to produce polyploids like colchicine treatment are explained. The document also discusses applications of aneuploids, autopolyploids and allopolyploids in crop improvement through techniques like trisomic analysis and chromosome substitution. Both advantages and limitations of polyploidy in plant breeding are summarized.
Sex aberrations
This document discusses various chromosomal abnormalities and genetic syndromes. It notes that 50% of spontaneous abortions are due to chromosomal abnormalities such as triploidy, Turner syndrome, and trisomy 16. It then describes several specific genetic syndromes including Klinefelter syndrome, Turner syndrome, Jacob's syndrome, triple X syndrome, and deletions or deficiencies of chromosomes 5, 15, and 22 associated with conditions like Cri-du-chat syndrome and Prader-Willi syndrome. The document concludes by discussing the goals of the Human Genome Project to better understand genetic variations and promote inclusion of those with differences.
The Electrocardiogram - Physiologic Principles
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Ketone bodies and metabolism-biochemistry
This slide consists of all the topics of ketone . This can be used for exam purpose for writing about Diabetic keto acidosis etc . Thank you
More Related Content
Similar to Lethal Gene.pptx
Complete Genetics
This document provides an overview of genetics concepts including classical genetics, molecular genetics, and evolutionary genetics. It discusses Mendel's laws of inheritance including dominance, segregation, and independent assortment. It defines key genetics terms like genotype, phenotype, homozygous, heterozygous, alleles, and genes. It also covers exceptions to Mendel's laws including incomplete dominance, codominance, and lethal alleles. Finally, it discusses linkage and crossing over between genes located on the same chromosome.
Lethal genes and gene therapy
This document provides information about lethal genes and gene therapy. It defines lethal genes as genes that reduce viability or cause death. It describes different types of lethal alleles such as early onset, late onset, conditional, and semi-lethal. Examples of dominant and recessive lethal genes are discussed, including diseases like Huntington's disease and conditions in mice coat color. Gene therapy is introduced as a way to insert normal genes to treat diseases caused by defective genes. The two main approaches of gene therapy - ex vivo and in vivo - are outlined. Viral and non-viral vectors used to deliver genes are also summarized.
Post-Mendelian Genetics
This presentation offers an interaction about Post-Mendelian genetics overview with special refrence4 to Mono-hybrid interaction.
Mendelian genetics
This document provides definitions and explanations of key concepts in Mendelian genetics. It discusses Mendel's laws of segregation, independent assortment, and dominance. It also summarizes exceptions to Mendelian ratios, including lethal alleles, incomplete dominance, codominance, and other factors like epistasis, pleiotropy, genetic heterogeneity, variable expressivity, and incomplete penetrance.
lethal genes
1. Lethal genes are genes that cause death or reduced viability when carried by an individual. They can be dominant or recessive.
2. Some examples of lethal genes discussed are Huntington's disease, cystic fibrosis, sickle cell anemia, and coat color genes in mice.
3. Gene therapy aims to treat diseases caused by defective genes by inserting functional genes. It can target somatic or germ-line cells. Viral and non-viral vectors are used to deliver therapeutic genes.
Genetic
This document discusses human genetics and genetic disorders. It begins by noting statistics on genetic abnormalities in newborns and diseases with a genetic component. It then defines genetics, genomics, proteomics, and single nucleotide polymorphisms. The rest of the document discusses molecular bases of human disease including functional and positional cloning. It classifies human diseases and discusses mutations, Mendelian disorders, X-linked disorders, and autosomal dominant and recessive patterns of inheritance. Key points covered include definitions of genetic terms, Mendel's laws of inheritance, mechanisms of various disorders, and inheritance patterns.
GENETIC DISORDER IN LIVESTOCK ANIMAL
Genetic disorders can occur in livestock animals due to mutations in genes or chromosomal abnormalities. In cattle, common genetic disorders include dwarfism, osteopetrosis (marble bone disease), tibia hemimelia, and pulmonary hypoplasia with anasarca. Sheep disorders include spider lamb syndrome and rectal prolapse. Chicken disorders include bent toes and split wings. Goats can experience epidermolysis bullosa or the fainting goat condition. Prevention of genetic disorders in livestock is important for economic reasons and involves selective breeding practices like culling affected animals and avoiding inbreeding to reduce homozygosity.
Balanced lethal system
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.
Molecular basis of genetic disease
Brief description on mendelian and non mendelian inheritance for undergraduate and post graduate learning
10. patterns of inheritance
Gregor Mendel's pea plant experiments in the mid-19th century laid the groundwork for genetics by demonstrating that traits are passed from parents to offspring via discrete units of inheritance called genes. The document defines genetic terminology like alleles, genotypes, phenotypes, dominant/recessive traits, and describes Mendel's laws of segregation and independent assortment. It also discusses sex-linked inheritance and variations like incomplete dominance and polygenic traits. Common human genetic disorders are reviewed including examples like sickle cell disease, cystic fibrosis, and Duchenne muscular dystrophy.
16. Lecture 16 Lethel genes, pleiotropy.ppt
The document discusses several genetics concepts:
1. Lethal genes can cause death before or after birth if both alleles are present, as seen in creeper chickens where the expected 3:1 ratio is instead 2:1.
2. Pleiotropy occurs when a single gene influences multiple traits, like sickle-cell anemia affecting hemoglobin and health.
3. Penetrance refers to the proportion of individuals that exhibit phenotypic effects of a gene, which can be complete or incomplete. Expressivity is the degree of phenotypic expression.
4. Multiple alleles exist at a single locus, like the four fur colors in rabbits controlled by Agouti, Chinchilla, Himalayan, and Al
Which statement describes a similarity between the diploid and haplo.pdf
Which statement describes a similarity between the diploid and haploid phases of plant life?
A zygote is formed ____.
Human skin color is an example of ____, while sickle-cell anemia is an example of ____.both
are multicellular
Solution
1. both are multicellular.
The plant life cycle alternates between haploid and diploid generations.Plants have multicellular
haploid and multicellular diploid stages in their life cycle.Gametes develop in the multicellular
haploid gametophyte.Fertilization gives rise to a multicellular diploid sporophyte,which
produces haploid spores via meiosis.
2.Zygote is formed by the fusion of egg and sperm nuclei.
In human fertilization,ovum which is a haploid secondary oocyte and a haploid sperm cell
combine to form a single 2n diploid cell called the zygote.
In fungi,the sexual fusion of haploid cells is called karyogamy.This cell may then enter meiosis
or mitosis depending on the life cycle of the species.
In plants,the zygote may be polyploid if fertilization occurs between meiotically unreduced
gametes.
Somatic cells are other than reproductive cells.Zygote formation occurs in reproductive cells.
3.Human skin color is an example of polygenic inheritance, while sickle-cell anemia is an
example of pleiotropy.
Polygenic inheritance occurs when one characteristic is controlled by two or more genes.Skin
color is largely determined by the amount of melanin. Dark skinned individuals produce more
melanin than light skinned individuals.At least three genes regulate the amount of melanin
produced. Each gene has two forms: dark skin allele (A,B,and C) and light skin allele (a,b,and c).
Pleiotropy occurs when variation at a single gene locus affects multiple aspects of the
phenotype.Sickle cell anemia is a genetic disease that causes deformed red blood cells with a
rigid,crescent shape instead of the normal flexible,round shape.It is caused by a change in one
nucleotide in the HBB gene.Sickle cell anemia occurs when the HBB gene mutation causes both
beta-globin subunits of hemoglobin to change into hemoglobin S..
ppt on the modificationn_of_mendelian_ratio.pptx
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 interaction ppt
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.
Lethal allele
This document discusses lethal alleles, which are alleles that cause death in an organism. It defines lethal alleles and provides a brief history of their discovery through early studies of coat color inheritance in mice. The document outlines four types of lethal alleles: early onset alleles that cause death early in life, late onset alleles that cause death late in life, conditional alleles that only cause death under certain environmental conditions, and semi-lethal alleles that only kill some individuals, not all. It provides the example of the Y gene in mice, which causes a yellow coat color but is lethal when present in the homozygous dominant state (YY), though not in the heterozygous or recessive states.
Gene Defects
1) Gene mutations and chromosomal abnormalities can cause a variety of genetic disorders and diseases.
2) A single base pair change in DNA can cause mutations like sickle cell anemia, while errors in meiosis can result in aneuploidies including extra or missing chromosomes.
3) Examples of genetic disorders include Tay-Sachs disease, cystic fibrosis, Huntington's disease, and Down syndrome which is caused by trisomy 21. These disorders alter genes and result in physical or mental impairments.
TRADITIONAL INHERITANCE
The modern scientific era begins with the work of Austrian monk, Gregor Mendel, who in 1865 presented the results of his breeding experiments on contrasting characters in garden peas
Mendel's laws of inheritance
Dominant inheritance
Dominant mutations are expressed when only one copy of that mutation is present. Therefore, anyone who inherits one dominant disease mutation such as the mutation for Huntington’s disease will have that disease.
Dominantly inherited genetic diseases tend to occur in every generation of a family. Each affected person usually has one affected parent.
However, dominant mutations can also happen in an individual for the first time, with no family history of the condition (spontaneous mutation).
Patterns of Inheritance
This document discusses several patterns of inheritance including:
1. Dominant and recessive genes and how they determine traits like coat color in mice.
2. Lethal alleles that cause death in homozygous dominant genotypes.
3. Incomplete dominance and codominance where both alleles are partially or fully expressed.
4. Sex linkage and how traits on the X chromosome are inherited differently between males and females.
It also discusses environmental influences on gene expression and abnormal chromosome numbers leading to conditions like Down syndrome.
Lecture 27 - Polyploidy breeding.ppt
This document discusses polyploidy in plant breeding. It defines key terms like diploidy, polyploidy, haploidy, and aneuploidy. It describes different types of polyploids like autopolyploids which have identical genomes, and allopolyploids which have distinct genomes. Methods to produce polyploids like colchicine treatment are explained. The document also discusses applications of aneuploids, autopolyploids and allopolyploids in crop improvement through techniques like trisomic analysis and chromosome substitution. Both advantages and limitations of polyploidy in plant breeding are summarized.
Sex aberrations
This document discusses various chromosomal abnormalities and genetic syndromes. It notes that 50% of spontaneous abortions are due to chromosomal abnormalities such as triploidy, Turner syndrome, and trisomy 16. It then describes several specific genetic syndromes including Klinefelter syndrome, Turner syndrome, Jacob's syndrome, triple X syndrome, and deletions or deficiencies of chromosomes 5, 15, and 22 associated with conditions like Cri-du-chat syndrome and Prader-Willi syndrome. The document concludes by discussing the goals of the Human Genome Project to better understand genetic variations and promote inclusion of those with differences.
Similar to Lethal Gene.pptx (20)
Which statement describes a similarity between the diploid and haplo.pdf
Which statement describes a similarity between the diploid and haplo.pdf
Recently uploaded
The Electrocardiogram - Physiologic Principles
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Ketone bodies and metabolism-biochemistry
This slide consists of all the topics of ketone . This can be used for exam purpose for writing about Diabetic keto acidosis etc . Thank you
TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd...
TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd Edition by DeMarco, Walsh, Verified Chapters 1 - 25, Complete Newest Version TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd Edition by DeMarco, Walsh, Verified Chapters 1 - 25, Complete Newest Version TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd Edition by DeMarco, Walsh, Verified Chapters 1 - 25, Complete Newest Version Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Pdf Chapters Download Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Pdf Download Stuvia Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Study Guide Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Ebook Download Stuvia Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Questions and Answers Quizlet Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Studocu Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Quizlet Test Bank For Community and Public Health Nursing: Evidence for Practice 3rd Edition Stuvia Community and Public Health Nursing: Evidence for Practice 3rd Edition Pdf Chapters Download Community and Public Health Nursing: Evidence for Practice 3rd Edition Pdf Download Course Hero Community and Public Health Nursing: Evidence for Practice 3rd Edition Answers Quizlet Community and Public Health Nursing: Evidence for Practice 3rd Edition Ebook Download Course hero Community and Public Health Nursing: Evidence for Practice 3rd Edition Questions and Answers Community and Public Health Nursing: Evidence for Practice 3rd Edition Studocu Community and Public Health Nursing: Evidence for Practice 3rd Edition Quizlet Community and Public Health Nursing: Evidence for Practice 3rd Edition Stuvia Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Pdf Chapters Download Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Pdf Download Stuvia Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Study Guide Questions and Answers Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Ebook Download Stuvia Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Questions Quizlet Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Studocu Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Quizlet Community and Public Health Nursing: Evidence for Practice 3rd Edition Test Bank Stuvia
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler, Verified Chapters 1 - 33, Complete Newest Version Community Health Nursing A Canadian Perspective, 5th Edition by Stamler Community Health Nursing A Canadian Perspective, 5th Edition TEST BANK by Stamler Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Study Guide Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Stuvia Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Studocu Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Test Bank For Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Pdf Download Course Hero Community Health Nursing A Canadian Perspective, 5th Edition Answers Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Ebook Download Course hero Community Health Nursing A Canadian Perspective, 5th Edition Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Studocu Community Health Nursing A Canadian Perspective, 5th Edition Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Chapters Download Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Pdf Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Study Guide Questions and Answers Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Ebook Download Stuvia Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Questions Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Studocu Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Quizlet Community Health Nursing A Canadian Perspective, 5th Edition Test Bank Stuvia
The Nervous and Chemical Regulation of Respiration
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
Top-Vitamin-Supplement-Brands-in-India List
Swisschem Dermacare provides the Top 10 Vitamin Supplement Brands in India. To know more about us give us call at our official number
REGULATION FOR COMBINATION PRODUCTS AND MEDICAL DEVICES.pptx
It includes regulation of combination products and medical devices. FDA and industry liaisons.
Adhd Medication Shortage Uk - trinexpharmacy.com
The UK is currently facing a Adhd Medication Shortage Uk, which has left many patients and their families grappling with uncertainty and frustration. ADHD, or Attention Deficit Hyperactivity Disorder, is a chronic condition that requires consistent medication to manage effectively. This shortage has highlighted the critical role these medications play in the daily lives of those affected by ADHD. Contact : +1 (747) 209 – 3649 E-mail : sales@trinexpharmacy.com
Histololgy of Female Reproductive System.pptx
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Explore the benefits of combining Ayurveda with conventional Parkinson's treatments. Learn how a holistic approach can manage symptoms, enhance well-being, and balance body energies. Discover the steps to safely integrate Ayurvedic practices into your Parkinson’s care plan, including expert guidance on diet, herbal remedies, and lifestyle modifications.
Clinic ^%[+27633867063*Abortion Pills For Sale In Tembisa Central
Clinic ^%[+27633867063*Abortion Pills For Sale In Tembisa Central Clinic ^%[+27633867063*Abortion Pills For Sale In Tembisa CentralClinic ^%[+27633867063*Abortion Pills For Sale In Tembisa CentralClinic ^%[+27633867063*Abortion Pills For Sale In Tembisa CentralClinic ^%[+27633867063*Abortion Pills For Sale In Tembisa Central
Top Effective Soaps for Fungal Skin Infections in India
Swisschem Dermacare has mentioned the List of The Best Antifungal Soap In India 2022. All of these soaps are trusted by various Dermatology Experts.
Recently uploaded (20)
TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd...
TEST BANK For Community and Public Health Nursing: Evidence for Practice, 3rd...
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...
The Nervous and Chemical Regulation of Respiration
The Nervous and Chemical Regulation of Respiration
REGULATION FOR COMBINATION PRODUCTS AND MEDICAL DEVICES.pptx
REGULATION FOR COMBINATION PRODUCTS AND MEDICAL DEVICES.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Muscles of Mastication by Dr. Rabia Inam Gandapore.pptx
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Integrating Ayurveda into Parkinson’s Management: A Holistic Approach
Clinic ^%[+27633867063*Abortion Pills For Sale In Tembisa Central
Clinic ^%[+27633867063*Abortion Pills For Sale In Tembisa Central
Top Effective Soaps for Fungal Skin Infections in India
Top Effective Soaps for Fungal Skin Infections in India
Lethal Gene.pptx
- 3. Definition: Genes which result in viability reduction of individual or become a cause for death of individuals carrying them are called lethal genes. Some lethal genes cause death of zygote or the early embryonic stage while some express their effect in later stages of development. Certain genes are absolutely essential for survival. Mutation in these genes creates lethal allele.
- 4. History Lethal genes was first discovered by Lucien Cuenot while studying the inheritance of coat colour in mice. He expected a phenotype ratio from a cross of 3 yellow: 1 white, but the observed ratio was 2:1. Allele was lethal in homozygous dominant condition.
- 6. 1. Recessive lethal: Most of the lethal genes are recessive lethals. It is expressed only when they are in homozygous condition. The survival of heterozygotes is not affected e.g., coat colour in mice. According to Cuenot, Castle and Little, the dominant allele Y is a recessive lethal and it causes death of homozygous YY embryos at an early stage of development. 2. Dominant lethal: There are some lethal genes which reduce viability even in heterozygotes, are said as dominant lethals. e.g., epiloia gene in human beings. This cause mental defects, abnormal skin growth and tumors in heterozygotes, therefore, they die before reaching adulthood. The dominant lethals may be produced in every generation through mutation. Explanation : TT Tt tt
- 7. 3. Conditional lethal: The lethal genes require a definite or specific condition for their lethal action are said as conditional lethals. Many mutants of barley, maize, Neurospora, Drosophila and many other organisms are termed as temperature sensitive mutations. Each of them needs a definite, generally high temperature to express their lethal action. A chlorophyll mutant of barley allows normal chlorophyll development at a temperature of 19°C or above, but it develops albina or abnormal white seedlings at temperature below 8°C. Temperature is not only responsible to bring out conditional lethals. Some conditional lethals require light, nutrition etc.
- 8. Lethal Gene in Mouse Y gene in mouse: Y gene is responsible for yellow coat color in mouse. In recessive condition it produces white color. Allele Y is lethal only when it present in homozygous dominant condition (YY). But this allele is not lethal in heterozygous dominant (Yy) conditions.
- 10. Feel free to ask any questions