1. The document discusses gene interactions and how they can modify Mendelian ratios by altering phenotypic expression. It provides examples of different types of epistatic interactions like complementary, duplicate, dominant, and recessive gene interactions.
2. It also covers complementation analysis, which is used to determine if two mutations causing the same phenotype are in the same or different genes. If the mutations complement, producing wild-type offspring, they are in different genes, while failure to complement means they are in the same gene.
3. The functional consequences of mutations are described as either loss-of-function, reducing or eliminating gene activity, or gain-of-function, conferring new or enhanced activity. Specific types
This document defines epigenetics as heritable changes in gene expression that are not caused by changes in DNA sequence. It discusses genomic imprinting, where alleles from the father and mother are expressed differently. Genomic imprinting is explained by the parental conflict theory, which posits that genes have evolved conflicting interests in how much they provision offspring depending on whether they are inherited from the father or mother. Imprinting marks on DNA are established differently depending on the parent of origin and can be erased in germ line cells, but reestablished in offspring. Problems can occur if imprinting marks are defective or the wrong parental alleles are inherited.
Mutations,natural selection and speciationbhavnesthakur
Mutations, natural selection, and speciation were the topics covered. The key points discussed include:
1. Mutations are sudden, inheritable changes in genetic material that can be caused by factors like radiation, chemicals, or replication errors. They can be beneficial, harmful, or neutral.
2. Natural selection occurs when heritable traits influence the reproductive success of organisms, meaning mutations that increase fitness are more likely to be passed on.
3. Over time, accumulation of genetic differences through natural selection and mutations can lead to the emergence of new species in a process known as speciation.
Oxytocin and vasopressin are peptide hormones produced in the hypothalamus and released from the posterior pituitary gland. Oxytocin regulates milk release and uterine contractions during labor, while vasopressin regulates water balance. Both hormones have similar structures but different physiological roles. Oxytocin is involved in romantic attachment, sexual response, social behaviors, and wound healing by reducing anxiety and inflammation. Vasopressin regulates water reabsorption in the kidneys to maintain fluid homeostasis and also mediates blood pressure responses. Diseases related to these hormones include diabetes insipidus and syndrome of inappropriate vasopressin secretion.
Chromosomal theory of inheritance in relation to cell divisionBipashaDatta1
This document describes the chromosomal theory of inheritance proposed by Sutton and Boveri in 1903. They concluded that chromosomes contain genes which govern the transmission of characters from parents to offspring, establishing chromosomes as the physical basis of inheritance. The theory was supported by evidence including sex chromosomes, sex linkages, and structural chromosomal changes observed through experiments in grasshoppers. The document then provides details about cell division, the cell cycle, mitosis, meiosis, and compares the key differences between mitosis and meiosis.
Mutations are changes in the nucleotide sequence of genes. They can be point mutations like substitutions, insertions, or deletions of single nucleotides, or large-scale mutations involving larger chromosomal changes. Mutations can arise spontaneously from errors in DNA replication or DNA damage, or be induced by mutagens like chemicals, radiation, or viruses. Point mutations can cause silent, missense, or nonsense changes to proteins, while frameshift mutations alter the reading frame. Mutations can have harmful, beneficial, or no effects depending on their location and type of genetic change.
1. The document discusses factors that can initiate microevolution by changing gene frequencies in populations.
2. It explains that microevolution occurs within populations and involves changes in gene frequency over time due to factors like mutation, natural selection, genetic drift, non-random mating, and gene flow.
3. For a population to evolve, at least one of the five conditions of Hardy-Weinberg equilibrium must be absent - no mutations, random mating, no natural selection, extremely large population size, or no gene flow.
This document summarizes different ways that enzyme activity can be regulated in cells, including at the level of production, compartmentation, activation/inhibition, post-translational modification, and localization. It describes constitutive enzymes that are always active and regulated enzymes that are only active under certain conditions. Enzyme activity can be regulated at the level of transcription/translation or after protein synthesis via posttranslational modification. Mechanisms of regulation include feedback inhibition, allosteric regulation of activity based on substrate or product binding, phosphorylation/dephosphorylation, and proteolytic activation.
This document discusses different concepts related to genetics including complete and incomplete dominance, codominance, multiple alleles, and sex determination.
It provides snapdragons with red, white, and pink flowers as an example of codominance, where the alleles for red (R) and white (r) both influence the phenotype and result in pink (Rr) flowers. It also gives human blood types as an example of multiple alleles, where the IA, IB, and Io alleles determine blood type A, B, AB, or O.
The document then provides a genetics problem asking for the possible blood groups of children from a mother with blood type A and a father with blood type B. It works through the
This document defines epigenetics as heritable changes in gene expression that are not caused by changes in DNA sequence. It discusses genomic imprinting, where alleles from the father and mother are expressed differently. Genomic imprinting is explained by the parental conflict theory, which posits that genes have evolved conflicting interests in how much they provision offspring depending on whether they are inherited from the father or mother. Imprinting marks on DNA are established differently depending on the parent of origin and can be erased in germ line cells, but reestablished in offspring. Problems can occur if imprinting marks are defective or the wrong parental alleles are inherited.
Mutations,natural selection and speciationbhavnesthakur
Mutations, natural selection, and speciation were the topics covered. The key points discussed include:
1. Mutations are sudden, inheritable changes in genetic material that can be caused by factors like radiation, chemicals, or replication errors. They can be beneficial, harmful, or neutral.
2. Natural selection occurs when heritable traits influence the reproductive success of organisms, meaning mutations that increase fitness are more likely to be passed on.
3. Over time, accumulation of genetic differences through natural selection and mutations can lead to the emergence of new species in a process known as speciation.
Oxytocin and vasopressin are peptide hormones produced in the hypothalamus and released from the posterior pituitary gland. Oxytocin regulates milk release and uterine contractions during labor, while vasopressin regulates water balance. Both hormones have similar structures but different physiological roles. Oxytocin is involved in romantic attachment, sexual response, social behaviors, and wound healing by reducing anxiety and inflammation. Vasopressin regulates water reabsorption in the kidneys to maintain fluid homeostasis and also mediates blood pressure responses. Diseases related to these hormones include diabetes insipidus and syndrome of inappropriate vasopressin secretion.
Chromosomal theory of inheritance in relation to cell divisionBipashaDatta1
This document describes the chromosomal theory of inheritance proposed by Sutton and Boveri in 1903. They concluded that chromosomes contain genes which govern the transmission of characters from parents to offspring, establishing chromosomes as the physical basis of inheritance. The theory was supported by evidence including sex chromosomes, sex linkages, and structural chromosomal changes observed through experiments in grasshoppers. The document then provides details about cell division, the cell cycle, mitosis, meiosis, and compares the key differences between mitosis and meiosis.
Mutations are changes in the nucleotide sequence of genes. They can be point mutations like substitutions, insertions, or deletions of single nucleotides, or large-scale mutations involving larger chromosomal changes. Mutations can arise spontaneously from errors in DNA replication or DNA damage, or be induced by mutagens like chemicals, radiation, or viruses. Point mutations can cause silent, missense, or nonsense changes to proteins, while frameshift mutations alter the reading frame. Mutations can have harmful, beneficial, or no effects depending on their location and type of genetic change.
1. The document discusses factors that can initiate microevolution by changing gene frequencies in populations.
2. It explains that microevolution occurs within populations and involves changes in gene frequency over time due to factors like mutation, natural selection, genetic drift, non-random mating, and gene flow.
3. For a population to evolve, at least one of the five conditions of Hardy-Weinberg equilibrium must be absent - no mutations, random mating, no natural selection, extremely large population size, or no gene flow.
This document summarizes different ways that enzyme activity can be regulated in cells, including at the level of production, compartmentation, activation/inhibition, post-translational modification, and localization. It describes constitutive enzymes that are always active and regulated enzymes that are only active under certain conditions. Enzyme activity can be regulated at the level of transcription/translation or after protein synthesis via posttranslational modification. Mechanisms of regulation include feedback inhibition, allosteric regulation of activity based on substrate or product binding, phosphorylation/dephosphorylation, and proteolytic activation.
This document discusses different concepts related to genetics including complete and incomplete dominance, codominance, multiple alleles, and sex determination.
It provides snapdragons with red, white, and pink flowers as an example of codominance, where the alleles for red (R) and white (r) both influence the phenotype and result in pink (Rr) flowers. It also gives human blood types as an example of multiple alleles, where the IA, IB, and Io alleles determine blood type A, B, AB, or O.
The document then provides a genetics problem asking for the possible blood groups of children from a mother with blood type A and a father with blood type B. It works through the
An overview on mutation, the general mechanisms, classification based on various characteristics, analogy sentence and genetic disorder of various types based on its classification, a brief description of mutagens agents and consequences of mutation in our body and on other living creatures
Molecular & genetic mechanisms of onto genesisEneutron
1) The document discusses various mechanisms of sexual and asexual reproduction in organisms. It describes gametogenesis, fertilization, and the main stages of ontogenesis including cleavage, gastrulation, and formation of organs and systems.
2) The two main types of reproduction are asexual, which produces offspring genetically identical to the parent, and sexual, which involves meiosis and fusion of male and female gametes to create offspring with genetic material from both parents.
3) Fertilization is the fusion of haploid gametes to form a diploid zygote, which then undergoes cleavage, gastrulation, and organogenesis during development.
Mutations are heritable changes in an organism's genetic material. They arise from errors in DNA replication or distribution and can cause sudden changes in characteristics. There are two main types of mutations - gene mutations, which alter the sequence of a single gene, and chromosomal mutations, which involve changes in chromosome number or structure. Point mutations specifically change a single DNA nucleotide, and can be further classified as transitions, transversions, nonsense, missense, or silent mutations depending on their effects. Frameshift mutations insert or delete DNA nucleotides, altering the reading frame and resulting in abnormal proteins. Many diseases like cystic fibrosis, sickle cell anemia, and cancer are caused by specific point or frameshift mutations.
Mendel conducted experiments with pea plants to develop his laws of heredity. Through crosses involving one or two traits, he discovered that traits are passed to offspring through discrete units (now known as genes and alleles) and that alleles segregate and assort independently. His laws of segregation and independent assortment explained inheritance patterns through generations and the ratios of traits in offspring. Mendel's work established genetics as a science and his principles remain fundamental to inheritance.
Chapter 15: Chromosomal Basis of InheritanceAngel Vega
KEY CONCEPTS
15.1 Morgan showed that Mendelian inheritance has its physical
basis in the behavior of chromosomes: Scientific inquiry
15.2 Sex-linked genes exhibit unique patterns of inheritance
15.3 Linked genes tend to be inherited together because they are located near each other on the same chromosome
15.4 Alterations of chromosome number or structure cause
some genetic disorders
15.5 Some inheritance patterns are exceptions to standard
Mendelian inheritance
Ch08 lecture inheritance, genes, and chromosomesTia Hohler
This document provides an overview of inheritance, genes, and chromosomes. It summarizes Gregor Mendel's experiments with pea plants that established the laws of inheritance, including the law of segregation and the law of independent assortment. It describes how genes are located on chromosomes and can be linked or unlinked. It discusses genetic mapping and recombination frequencies to determine the arrangement of genes on chromosomes. Overall, the document outlines key concepts in classical genetics and inheritance patterns established by Mendel's work.
This presentation on Epigenetics is most advanced and evidence based one. Its Very helpful for Genetics students and research fellows, Reproductive Medicine specialist, Reproductive Biologist, Infertility practitioners
This document discusses phylogenetic studies and the construction of phylogenetic trees. It notes that fossil records are unreliable, so phylogenetic trees are primarily based on molecular sequencing data and morphological data. There are several assumptions made in phylogenetic analysis, including that sequences are homologous, phylogenetic divergence is bifurcating, and each position in a sequence evolved independently. The document outlines different types of phylogenetic trees, steps in phylogenetic analysis like choosing molecular markers and tree building methods, and criteria for assessing the reliability of phylogenetic trees.
Eukaryotic chromosomes are made of DNA and proteins. A gene is a heritable factor that controls a specific characteristic. Alleles are different forms of the same gene that occupy the same locus. A genome is the complete set of genetic material of an organism. Gene mutations, such as base substitutions, can occur which may lead to genetic disorders like sickle-cell anemia caused by a mutation replacing glutamic acid with valine.
The document discusses the cytoskeleton, which is composed of microfilaments, intermediate filaments, and microtubules. Microfilaments are composed of actin and are involved in cell motility and structure. Intermediate filaments provide mechanical strength and support cellular structures. Microtubules are composed of tubulin and are involved in maintaining cell shape and intracellular transport. The cytoskeleton is a dynamic network that maintains cell structure and enables various cell functions and movements.
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.
Mutations are changes in genetic material that can be harmful, beneficial, or neutral. There are two types of mutations: somatic mutations, which occur in body cells and are not passed to offspring, and germline mutations, which occur in sex cells and can be inherited. Germline mutations are more relevant for evolution and are generally what is meant by the term "mutation". Mutations can be caused by errors in DNA replication, environmental mutagens like radiation or chemicals, or due to changes in DNA base pairing. They result in changes at the DNA level like substitutions, insertions, deletions, and can have various effects at the protein and phenotypic levels.
Co-Enzyme and their Role in Regulation in Metabolic Process Presented By Waqa...waqassiddiqe
Co-enzymes play an essential role in metabolism by helping enzymes catalyze reactions. Many co-enzymes contain adenosine monophosphate and assist reactions by carrying atoms or groups between enzymes. Coenzyme A is a key player by activating metabolic pathways and facilitating enzyme recognition through formation of acyl-CoA thioesters. Maintaining adequate metabolic enzyme levels is important for health, as deficiencies can result from factors like pesticide exposure, excess heated foods, or pancreatic conditions.
Gregor Mendel conducted experiments with pea plants in the 1860s to develop an understanding of heredity. He studied seven traits in pea plants and found that traits are passed to offspring through discrete factors, now called genes. His experiments led him to formulate the laws of inheritance, including the law of dominance, the law of segregation, and the law of independent assortment. Mendel's principles explained inheritance in a way that was ahead of scientific understanding at the time and formed the foundation of modern genetics.
This document discusses metabolism and energy transformations in living systems. It covers topics like thermodynamics, metabolic pathways, oxidation-reduction reactions, and experimental approaches to study metabolism. Key points include:
- ATP is used as the main "currency" of energy in cells and is generated by catabolic reactions and used by anabolic reactions.
- Electron transfer reactions and phosphorylation group transfers are two major mechanisms for energy transfer in biological systems.
- Metabolic pathways are organized series of chemical reactions that are regulated and sometimes compartmentalized within cells.
- Experimental techniques like isolating enzymes and studying genetic defects help uncover regulatory mechanisms and blocked steps in metabolism.
Mutations can be caused by errors during DNA replication or by environmental mutagens. There are two main types of mutations: germline mutations, which can be inherited, and somatic mutations, which cannot. Mutations can involve changes to a single nucleotide (point mutation) or larger structural changes to chromosomes. DNA repair systems help fix errors, with mechanisms like base excision repair, nucleotide excision repair, and mismatch repair that recognize and correct damage. Unrepaired mutations can lead to genetic disorders if they occur in germline cells or cause cancer if they happen in other body cells.
A genetic mutation is a permanent change in the nucleotide sequence of an organism's genome. Mutations can arise from unrepaired DNA or RNA damage, replication errors, or mobile genetic elements. They play a role in both normal and abnormal biological processes like evolution, cancer development, and the immune system. There are two main types of mutations: somatic mutations, which occur in non-reproductive cells and are not inherited, and germline mutations, which occur in reproductive cells and can be passed to offspring. Mutations can be classified in several ways based on their structure, function, protein effects, and inheritance patterns. They can arise spontaneously from DNA damage or errors, or be induced by chemicals, radiation, and other mutagens
INTRODUCTION
DISCOVREY OF MYOGLOBIN STRUCTURE
STRUCTURE OF MYOGLOBIN
APOMYOGLOBIN
MECHANISM-
BINDING OF OXYGEN TO MYGLOBIN
DISASSOCIATION OF OXYGEN FOROM MYOGLOBIN
IMPORTANT FEATURES OF MYOGLOBIN
BIOLOGICAL SIGNIFICANCES OF MYOGLOBIN
CONCLUSION
REFERENCES
This document discusses population variation and selection. It provides an overview of key concepts:
1. Natural selection acts on individuals but only populations evolve over generations as allele frequencies change. This was shown using a population of finches where large-beaked birds survived a drought better.
2. Three mechanisms can cause changes in allele frequencies in a population: natural selection, genetic drift, and gene flow. Natural selection is the only mechanism that causes adaptive evolution.
3. Genetic variation within populations is required for evolution. Variation comes from new mutations and recombination during sexual reproduction. The Hardy-Weinberg principle describes populations where allele frequencies remain constant without evolutionary influences.
Gene interactions can modify Mendelian ratios expected from monohybrid and dihybrid crosses. There are several types of gene interactions:
1. Complementary gene interaction results in a 9:7 ratio when two genes work together to produce a trait.
2. Duplicate gene action occurs when genes encode redundant functions, resulting in a 15:1 ratio.
3. Dominant gene interaction yields a 9:6:1 ratio when dominance of one gene masks the other.
4. Epistatic interactions alter Mendelian ratios by one gene modifying another's expression. This includes recessive epistasis (9:3:4 ratio) and dominant epistasis (12:3:1 ratio).
Genetic variation arises from four main sources: mutations, sexual reproduction, fertilization, and environmental influences. Mutations are changes in DNA that create new alleles and variations. Sexual reproduction and meiosis increase variation through independent assortment, crossing over, and random fertilization. A dihybrid cross examines inheritance of two traits controlled by separate genes. Mendel's dihybrid crosses on peas produced offspring in a 9:3:3:1 ratio, showing traits assort independently. Genetic variation allows populations to adapt to environmental changes over generations.
An overview on mutation, the general mechanisms, classification based on various characteristics, analogy sentence and genetic disorder of various types based on its classification, a brief description of mutagens agents and consequences of mutation in our body and on other living creatures
Molecular & genetic mechanisms of onto genesisEneutron
1) The document discusses various mechanisms of sexual and asexual reproduction in organisms. It describes gametogenesis, fertilization, and the main stages of ontogenesis including cleavage, gastrulation, and formation of organs and systems.
2) The two main types of reproduction are asexual, which produces offspring genetically identical to the parent, and sexual, which involves meiosis and fusion of male and female gametes to create offspring with genetic material from both parents.
3) Fertilization is the fusion of haploid gametes to form a diploid zygote, which then undergoes cleavage, gastrulation, and organogenesis during development.
Mutations are heritable changes in an organism's genetic material. They arise from errors in DNA replication or distribution and can cause sudden changes in characteristics. There are two main types of mutations - gene mutations, which alter the sequence of a single gene, and chromosomal mutations, which involve changes in chromosome number or structure. Point mutations specifically change a single DNA nucleotide, and can be further classified as transitions, transversions, nonsense, missense, or silent mutations depending on their effects. Frameshift mutations insert or delete DNA nucleotides, altering the reading frame and resulting in abnormal proteins. Many diseases like cystic fibrosis, sickle cell anemia, and cancer are caused by specific point or frameshift mutations.
Mendel conducted experiments with pea plants to develop his laws of heredity. Through crosses involving one or two traits, he discovered that traits are passed to offspring through discrete units (now known as genes and alleles) and that alleles segregate and assort independently. His laws of segregation and independent assortment explained inheritance patterns through generations and the ratios of traits in offspring. Mendel's work established genetics as a science and his principles remain fundamental to inheritance.
Chapter 15: Chromosomal Basis of InheritanceAngel Vega
KEY CONCEPTS
15.1 Morgan showed that Mendelian inheritance has its physical
basis in the behavior of chromosomes: Scientific inquiry
15.2 Sex-linked genes exhibit unique patterns of inheritance
15.3 Linked genes tend to be inherited together because they are located near each other on the same chromosome
15.4 Alterations of chromosome number or structure cause
some genetic disorders
15.5 Some inheritance patterns are exceptions to standard
Mendelian inheritance
Ch08 lecture inheritance, genes, and chromosomesTia Hohler
This document provides an overview of inheritance, genes, and chromosomes. It summarizes Gregor Mendel's experiments with pea plants that established the laws of inheritance, including the law of segregation and the law of independent assortment. It describes how genes are located on chromosomes and can be linked or unlinked. It discusses genetic mapping and recombination frequencies to determine the arrangement of genes on chromosomes. Overall, the document outlines key concepts in classical genetics and inheritance patterns established by Mendel's work.
This presentation on Epigenetics is most advanced and evidence based one. Its Very helpful for Genetics students and research fellows, Reproductive Medicine specialist, Reproductive Biologist, Infertility practitioners
This document discusses phylogenetic studies and the construction of phylogenetic trees. It notes that fossil records are unreliable, so phylogenetic trees are primarily based on molecular sequencing data and morphological data. There are several assumptions made in phylogenetic analysis, including that sequences are homologous, phylogenetic divergence is bifurcating, and each position in a sequence evolved independently. The document outlines different types of phylogenetic trees, steps in phylogenetic analysis like choosing molecular markers and tree building methods, and criteria for assessing the reliability of phylogenetic trees.
Eukaryotic chromosomes are made of DNA and proteins. A gene is a heritable factor that controls a specific characteristic. Alleles are different forms of the same gene that occupy the same locus. A genome is the complete set of genetic material of an organism. Gene mutations, such as base substitutions, can occur which may lead to genetic disorders like sickle-cell anemia caused by a mutation replacing glutamic acid with valine.
The document discusses the cytoskeleton, which is composed of microfilaments, intermediate filaments, and microtubules. Microfilaments are composed of actin and are involved in cell motility and structure. Intermediate filaments provide mechanical strength and support cellular structures. Microtubules are composed of tubulin and are involved in maintaining cell shape and intracellular transport. The cytoskeleton is a dynamic network that maintains cell structure and enables various cell functions and movements.
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.
Mutations are changes in genetic material that can be harmful, beneficial, or neutral. There are two types of mutations: somatic mutations, which occur in body cells and are not passed to offspring, and germline mutations, which occur in sex cells and can be inherited. Germline mutations are more relevant for evolution and are generally what is meant by the term "mutation". Mutations can be caused by errors in DNA replication, environmental mutagens like radiation or chemicals, or due to changes in DNA base pairing. They result in changes at the DNA level like substitutions, insertions, deletions, and can have various effects at the protein and phenotypic levels.
Co-Enzyme and their Role in Regulation in Metabolic Process Presented By Waqa...waqassiddiqe
Co-enzymes play an essential role in metabolism by helping enzymes catalyze reactions. Many co-enzymes contain adenosine monophosphate and assist reactions by carrying atoms or groups between enzymes. Coenzyme A is a key player by activating metabolic pathways and facilitating enzyme recognition through formation of acyl-CoA thioesters. Maintaining adequate metabolic enzyme levels is important for health, as deficiencies can result from factors like pesticide exposure, excess heated foods, or pancreatic conditions.
Gregor Mendel conducted experiments with pea plants in the 1860s to develop an understanding of heredity. He studied seven traits in pea plants and found that traits are passed to offspring through discrete factors, now called genes. His experiments led him to formulate the laws of inheritance, including the law of dominance, the law of segregation, and the law of independent assortment. Mendel's principles explained inheritance in a way that was ahead of scientific understanding at the time and formed the foundation of modern genetics.
This document discusses metabolism and energy transformations in living systems. It covers topics like thermodynamics, metabolic pathways, oxidation-reduction reactions, and experimental approaches to study metabolism. Key points include:
- ATP is used as the main "currency" of energy in cells and is generated by catabolic reactions and used by anabolic reactions.
- Electron transfer reactions and phosphorylation group transfers are two major mechanisms for energy transfer in biological systems.
- Metabolic pathways are organized series of chemical reactions that are regulated and sometimes compartmentalized within cells.
- Experimental techniques like isolating enzymes and studying genetic defects help uncover regulatory mechanisms and blocked steps in metabolism.
Mutations can be caused by errors during DNA replication or by environmental mutagens. There are two main types of mutations: germline mutations, which can be inherited, and somatic mutations, which cannot. Mutations can involve changes to a single nucleotide (point mutation) or larger structural changes to chromosomes. DNA repair systems help fix errors, with mechanisms like base excision repair, nucleotide excision repair, and mismatch repair that recognize and correct damage. Unrepaired mutations can lead to genetic disorders if they occur in germline cells or cause cancer if they happen in other body cells.
A genetic mutation is a permanent change in the nucleotide sequence of an organism's genome. Mutations can arise from unrepaired DNA or RNA damage, replication errors, or mobile genetic elements. They play a role in both normal and abnormal biological processes like evolution, cancer development, and the immune system. There are two main types of mutations: somatic mutations, which occur in non-reproductive cells and are not inherited, and germline mutations, which occur in reproductive cells and can be passed to offspring. Mutations can be classified in several ways based on their structure, function, protein effects, and inheritance patterns. They can arise spontaneously from DNA damage or errors, or be induced by chemicals, radiation, and other mutagens
INTRODUCTION
DISCOVREY OF MYOGLOBIN STRUCTURE
STRUCTURE OF MYOGLOBIN
APOMYOGLOBIN
MECHANISM-
BINDING OF OXYGEN TO MYGLOBIN
DISASSOCIATION OF OXYGEN FOROM MYOGLOBIN
IMPORTANT FEATURES OF MYOGLOBIN
BIOLOGICAL SIGNIFICANCES OF MYOGLOBIN
CONCLUSION
REFERENCES
This document discusses population variation and selection. It provides an overview of key concepts:
1. Natural selection acts on individuals but only populations evolve over generations as allele frequencies change. This was shown using a population of finches where large-beaked birds survived a drought better.
2. Three mechanisms can cause changes in allele frequencies in a population: natural selection, genetic drift, and gene flow. Natural selection is the only mechanism that causes adaptive evolution.
3. Genetic variation within populations is required for evolution. Variation comes from new mutations and recombination during sexual reproduction. The Hardy-Weinberg principle describes populations where allele frequencies remain constant without evolutionary influences.
Gene interactions can modify Mendelian ratios expected from monohybrid and dihybrid crosses. There are several types of gene interactions:
1. Complementary gene interaction results in a 9:7 ratio when two genes work together to produce a trait.
2. Duplicate gene action occurs when genes encode redundant functions, resulting in a 15:1 ratio.
3. Dominant gene interaction yields a 9:6:1 ratio when dominance of one gene masks the other.
4. Epistatic interactions alter Mendelian ratios by one gene modifying another's expression. This includes recessive epistasis (9:3:4 ratio) and dominant epistasis (12:3:1 ratio).
Genetic variation arises from four main sources: mutations, sexual reproduction, fertilization, and environmental influences. Mutations are changes in DNA that create new alleles and variations. Sexual reproduction and meiosis increase variation through independent assortment, crossing over, and random fertilization. A dihybrid cross examines inheritance of two traits controlled by separate genes. Mendel's dihybrid crosses on peas produced offspring in a 9:3:3:1 ratio, showing traits assort independently. Genetic variation allows populations to adapt to environmental changes over generations.
This document discusses meiosis and genetic linkage in plants and animals. It provides details on:
- The alternation of generations life cycle in plants, which involves a diploid sporophyte and haploid gametophyte stage.
- How crossing over during meiosis increases genetic variation by exchanging parts of homologous chromosomes.
- How the frequency of recombination between two genes indicates their distance on the same chromosome, and is used to construct genetic linkage maps.
This document provides information about genetics and Mendelian inheritance. It begins with an introduction to important figures in the history of genetics like Gregor Mendel. It then discusses the three main theories of inheritance pre-Mendel and the history of genetics including Mendel's experiments and laws of inheritance. The rest of the document details various genetics concepts like linkage, crossing over, aneuploidy and their relationships to chromosomes and inheritance patterns.
Weaver Molecular Biology 5th ed Chapter.1 presentationssuser11ca96
This chapter provides a brief history of molecular biology by discussing early concepts in transmission genetics, Mendel's laws of inheritance, the chromosome theory of inheritance, genetic mapping and recombination, the discovery that DNA is the molecule of heredity, the central dogma of molecular biology regarding DNA replication and gene expression, and the three domains of life - Bacteria, Archaea, and Eukaryota. The key events and concepts discussed include Mendel's laws, Morgan's work in Drosophila, the role of chromosomes, Avery's discovery that DNA carries genetic information, Watson and Crick's model of DNA structure, and the division of life into the three domains.
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.
Gregor Mendel conducted experiments with pea plants between 1856-1863. He found that when he cross-pollinated pea plants with distinct traits, the offspring displayed only one of the parental traits, and this trait was passed down predictably in future generations. His experiments demonstrated that traits are passed from parents to offspring through discrete units of inheritance, now known as genes, and established the fundamental principles of genetics including dominance, segregation of alleles, and independent assortment. Mendel's work formed the foundation of classical genetics.
1. Morgan's experiments with Drosophila showed that genes located close together on the same chromosome (linked genes) tend to be inherited together more often than expected by Mendel's law of independent assortment.
2. Crossing over during meiosis can lead to new combinations of linked genes, with the frequency of crossing over determining how far apart genes are on the genetic map.
3. Sturtevant used recombination frequencies between traits to construct the first genetic map, with map units called centimorgans representing a 1% chance of crossing over.
This document provides an overview of genetics and key concepts from Gregor Mendel's experiments. It introduces Mendel's work with pea plants and how he established the principles of heredity through monohybrid and dihybrid crosses. His work demonstrated that traits are inherited through discrete units called genes. The document also defines important genetic terminology and concepts such as dominant/recessive alleles, genotypes, phenotypes and Punnett squares. It discusses how Mendel's principles apply universally, using the example of cystic fibrosis inheritance in humans. The principle of independent assortment and exceptions like incomplete dominance in snapdragons are also summarized.
This document discusses genetic linkage and mapping techniques in eukaryotes. It defines linkage as genes failing to assort independently due to being located near each other on the same chromosome. Morgan's experiments with Drosophila showed that alleles can be inherited together or recombine during meiosis. The frequency of recombination between two linked genes provides their genetic distance in centimorgans on a linkage map. Techniques for mapping genes include testcrosses, estimating recombination frequencies in two-point and three-point crosses, and correcting for double crossovers.
This document discusses extensions of Mendelian genetics including incomplete dominance, codominance, multiple alleles, and gene interactions. It provides examples of incomplete dominance in flowers where the heterozygote has an intermediate phenotype. Codominance is explained using blood types where both alleles are expressed in the heterozygote. Multiple alleles are exemplified by the ABO blood group system which has three alleles. Gene interactions like epistasis can alter expected phenotypes when genes act together.
KEY CONCEPTS
14.1 Mendel used the scientific approach to identify two laws of inheritance
14.2 Probability laws govern Mendelian inheritance
14.3 Inheritance patterns are often more complex than predicted by simple Mendelian genetics
14.4 Many human traits follow Mendelian patterns of
inheritance
Mendel's laws of segregation and independent assortment govern inheritance. When crossing two heterozygotes with different alleles at the same locus, DaDb and DcDd, the alleles will segregate and assort independently. This results in offspring genotypes in a 1:2:1:2:1:2:1:1 ratio.
Mendel's laws of segregation and independent assortment govern inheritance patterns. When Mendel crossed two heterozygotes with different alleles at the same locus (DaDb x DcDd), he would expect the following genotype proportions in the offspring:
1) 9% DaDa, DbDb, DcDc, DdDd (homozygotes)
2) 24% DaDb, DaDc, DaDd, DbDc, DbDd, DcDd (heterozygotes)
3) 43% DaDc, DaDd, DbDc, DbDd (other heterozygotes)
The alleles assort independently during gamete formation, allowing for all possible combinations in a 9:
Genetics: The study of heredity.
Heredity is the relations between successive generations.
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This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
2. 4.3 Gene Interaction Modifies Mendelian
Ratios
• Genes work together to build the complex
structures and organ systems of plants and
animals
• The collaboration of multiple genes in the
production of a single phenotypic characteristic or
group of related characteristics is termed gene
interaction
3. • Geneticists use a variety of symbols for alleles
• Dominant alleles:
– an italic uppercase letter (D) or
– letters (Wr)
– an italic letter or group of letters with the + superscript (Wr+
)
• Recessive alleles:
– an italic lowercase letter (d) or
– an italic letter or group of letters (Wr)
Representing Alleles
S / Sm / Sm+
s / sm / Sm
Note that the mutant
usually gets the
letter name!
Note that the mutant
usually gets the
letter name!
4. Representing alleles in Drosophila
• Example: body color
– Ebony mutant phenotype is indicated by e
– Normal gray (wild-type) is indicated by e+
• e+
/e+
: gray homozygote (wild type)
• e+
/e: gray heterozygote (wild type)
• e/e: ebony homozygote (mutant)
OR
• +/+: gray homozygote (wild type)
• +/e: gray heterozygote (wild type)
• e/e: ebony homozygote (mutant)
5. Gene Interaction in Pathways
• Single-gene trait describes an inherited
variation of a gene that can produce a mutant
phenotype
• However, this is not a complete depiction of
genetic reality
• Numerous genes contribute to the normal red
eye color of Drosophila, including those
responsible for production of eye pigments or
transport proteins
6. Three Genes Involved in
Drosophila Eye Color
• The brown gene
produces an enzyme in
a pathway that
synthesizes a bright red
vermilion pigment;
mutant flies, bb, have
brown eyes
• Note: gene named after
the mutant, not the gene
it encodes for!
• The vermillion genes
produces an enzyme in
a pathway that
synthesizes a brown
pigment; mutant flies, vv,
have bright red eyes
• The white gene encodes
a transporter that carries
pigment to the eye; flies
that do not produce this
protein have white eyes
7. Three Distinct Types of Genetic Pathways
• Biosynthetic pathways are
networks of interacting genes
that produce a molecular
compound as their endpoint
• Signal transduction pathways
receive chemical signals from
outside a cell and initiate a
response inside the cell
• Developmental pathways direct
growth, development and
differentiation of body parts and
structures
8. HOW DO GENES CONTROL
BIOSYNTHETIC PATHWAYS?
HOW DO WE FIND A GENE
THAT AFFECTS A CERTAIN
PATHWAY?
Biosynthetic Pathways…
9. The One-Gene-One Enzyme Hypothesis
• George Beadle and Edward
Tatum were among the first to
investigate biosynthetic
pathways
• They studied growth variants of
the fungus, Neurospora crassa
• Their proposal, the one-gene-
one enzyme hypothesis came
out of their experiments
Red Bread Mold; http://www.biosci.missouri.edu/shiu/
10. Prototroph: an
organism that can
synthesize all of its
amino acids
Auxotroph: an
organism that has lost
the ability to
synthesize certain
substances required
for its growth and
metabolism
This experiment
looked at amino acids,
but you could look at
other synthetic
pathways!
Beadle and Tatum Experiment
CAUSING
MUTATION!
11. The Hypothesis Made a Connection
Between Genes, Proteins and Phenotypes
• Each gene produces
an enzyme
• Each enzyme has a
specific role in a
biosynthetic pathway
that produces the
phenotype
• Each mutant
phenotype due to
the loss or
malfunction of a
specific enzyme
12. Genetic Dissection to Investigate Gene
Action
• Biosynthetic pathways consist of sequential steps
• Completion of one step generates the substrate for the next
step in the pathway
• Completion of every step is necessary to produce the end
product
• Genetic dissection is an experimental approach taken to
investigate the steps of biosynthetic pathways
13. Genetic Dissections: Horowitz’s Experiments
on Met-
Mutants of Neurospora
• Horowitz’s analysis
aimed to:
• Determine the
number of
intermediate steps in
the methionine
synthesis pathway
• Determine the order
of the steps
• Identify the step
affected by each
mutation
14. Genetic Dissection: Results
of Horowitz’s Experiments
• Whether or not a mutant strain grows on a medium containing a component of the
pathway allows determination of the step at which the mutant is blocked
• Mutation of an enzyme will cause the pathway to become blocked.
• If we give an intermediate from before the block, we can’t pass the block and the mutant will not grow.
• If we give an intermediate after the block, the mutant will grow.
• The blocked step is also identified by the substance that accumulates in the
auxotroph
• Imagine one mutant:
X Give D, E or F: Will grow!Give A, B or C: Won’t grow!
What Accumulates?
15. 1. Met 1: only on minimal media + methionine, indicating it is the
last step of the pathway. Need to add methionine to get past the
block
2. Met 2: need minimal + homocysteine , therefore block is at step
that produces homocysteine. This result also tell us that
homocysteine is the substrate converted to methionine in the
biosynthetic pathway.
3. Met 3: grows on minimal, homocysteine &
cystathionine. This tells us that Met 3 is
blocked at the step that produces
cystathionine and that cystathionine
precedes homocysteine
4. Met 4 grows with any supplementation of
minimal media. This tells us that Met 4 is
defective at a step that precedes the
production of cysteine.
16. More Recent Adjustments to the Hypothesis
• Hypothesis confirmed!: Each gene produces an
enzyme
• Each enzyme has a specific role in a biosynthetic
pathway that produces the phenotype
• Recent Adjustments:
• Some protein producing genes produce transport
proteins, structural or regulatory proteins, rather
than enzymes
• Some genes produce RNAs rather than proteins
• Some proteins (e.g. β-globin) must join with other
proteins to acquire a function
17. So far…So far…
AaBb x AaBbAaBb x AaBb
Crossing genotypes leads to aCrossing genotypes leads to a
phenotypic ratiophenotypic ratio
BUT, Genes do not act alone.BUT, Genes do not act alone.
Now let’s look at how genesNow let’s look at how genes
interact to alter phenotypicinteract to alter phenotypic
ratios….ratios….
Gene InteractionsGene Interactions
18. Colorless
precursor
Colorless
intermediate
Purple
pigment
Enzyme C Enzyme P
The recessive c allele
encodes an inactive
enzyme
The recessive p allele
encodes an inactive
enzyme
Epistasis: Gene Interactions
• Epistatic interactions happen when an allele of one gene
modifies or prevents the expression of alleles at another
gene.
• Epistatic interactions often arise because two (or more)
different proteins participate in a common cellular
function
– For example, an enzymatic pathway
19. No Interaction (9:3:3:1 Ratio)
• The expected 9:3:3:1 ratio is
seen in the absence of
epistasis: when the genes do
not interact to change the
expression of one another
www.integratedbreeding.net
Dihybrid cross, F2 progeny
20. • Cross involving the brown and vermillion
genes in Drosophila
• When pure-breeding brown flies (b/b;
v+/v+) are crossed to pure-breeding
vermillion flies (b+/b+; v/v), the F1 all have
wild type red eyes (b+/b; v+/v)
• When the F1 are interbred (b+/b; v+/v x b+/b; v+/v ), the F2
are:
• 9/16 b+/-; v+/-, wild type, red eyes
• 3/16 b/b; v+/-, brown eyes
• 3/16 b+/-; v/v, vermillion eyes
• 1/16 b/b;v/v, white eyes
• The results show that the
genes are not undergoing
epistatic interaction with one
another
No Interaction (9:3:3:1 Ratio)
21. Epistatic Interactions
• A minimum of two genes are
required for epistatic
interactions; these usually
participate in the same pathway
• There are six ways epistasis
could affect the predicted
9:3:3:1 dihybrid ratio
22. Gene interaction alters the classic 9:3:3:1 ratio seen in the F2
progeny of the dihybrid cross!
Gene interaction alters the classic 9:3:3:1 ratio seen in the F2
progeny of the dihybrid cross!
Epistatic Interactions
23. Complementary Gene Interaction (9:7 Ratio)
• Bateson and Punnett crossed two pure-breeding strains of white flowered sweet peas
• They found all the F1 were purple flowered; the F1 x F1 cross yielded 9/16 purple and 7/16
white flowered progeny
• They recognized that the two genes interact to produce the overall flower
color; when genes work in tandem to produce a single gene product, it
is called complementary gene interaction
24. Duplicate Gene Action (15:1 Ratio)
• The genes in a redundant system have duplicate
gene action; they encode the same product, or they
encode products that have the same effect in a
pathway or compensatory pathways
25. Dominant Gene Interaction (9:6:1 Ratio)
• Plants that have dominant allele(s) for just one of either of the genes will have
round fruit and those with only recessive alleles of both genes will have long fruit
• Dominant for either gene (A or B), equals one phenotype. (3+3 = 6)
26. Recessive epistasis (9:3:4)
• B and b for black and brown melanin (MC1R gene)
• E: controls deposition of pigment in hairs (TRYP1 gene)
• ee is epistatic
• Recessive epistatsis causes yellow coat color
28. Dominant Epistasis (12:3:1 Ratio)
• In dominant epistasis, a dominant allele at one locus will
mask the phenotypic expression of the alleles at a second
locus, giving a 12:3:1 ratio
• E.g. in foxglove flowers a dominant allele at one locus
restricts the deposition of pigment to a small area of the
flower
29. Dominant Suppression (13:3 Ratio)
• In dominant suppression, a dominant allele at one locus completely
suppresses the phenotypic expression of the alleles at a second locus,
giving a 13:3 ratio
• In chickens, the C allele is responsible for pigmented feathers and the c allele for white
feathers
• The dominant allele of a second gene, I, can suppress the color producing effect of the C
allele, leading to white feathers in both C/- and c/c individuals
Dominant I suppresses dominant
pigment production
Dominant I suppresses dominant
pigment production
31. 4.4 Complementation Analysis Distinguishes
Mutations in the Same Gene from Mutations
in Different Genes
• When geneticists encounter organisms with the
same mutant phenotype, they ask two questions:
1. Do these organisms have mutations in the same
or in different genes?
2. How many genes are responsible for the
phenotypes observed?
Ex. Two botanists working with petunias both discover a white flower
mutation. One works in California and one works in the Netherlands.
Are the mutations in the same genes?
Ex. Two botanists working with petunias both discover a white flower
mutation. One works in California and one works in the Netherlands.
Are the mutations in the same genes?
32. HOW DO WE KNOW IF THE
GENETIC MUTATION IS THE
SAME?
We have two Drosophila with the same
phenotypic mutation….
33. Genetic Complementation
Analysis
• Genetic heterogeneity is when
mutations in different genes can
produce the same or very similar
mutant phenotypes
• Mating of two organisms with similar
mutant phenotypes can lead to wild
type offspring, a phenomenon called
genetic complementation
• Complementation testing is when two
pure breeding organisms with similar
mutant phenotypes are mated
• If complementation occurs, wild type
offspring are obtained and the
mutations are known to affect two
different genes
• When the mutations fail to
complement, the offspring have the
mutant phenotype and the mutations
are known to affect the same gene
Example of a complementation test.
Two strains of flies are white eyed because of two different
autosomal recessive mutations which interrupt different steps
in a single pigment-producing metabolic pathway.
A B
34. Complementation Analysis
• In complementation analysis
multiple crosses are performed
among numerous pure breeding
mutants to try to determine how
many different genes contribute
to a phenotype
• Mutations that mutually fail to
complement one another are
called a complementation
group
• Can’t get back to wild-type!
• Mutation is on the same gene!
• A complementation group in this
context refers to a gene
36. + = cross of pure-breeding mutants yield wild-type (complements)
- = cross of pure-breeding mutants yields only mutant progeny
+ = cross of pure-breeding mutants yield wild-type (complements)
- = cross of pure-breeding mutants yields only mutant progeny
-Mutations that fail to complement each other are on the same gene
-Complementation group: consist of one or mutants of a single gene
37. WHAT ARE THE FUNCTIONAL
CONSEQUENCES OF
MUTATION?
There are SO many different eye colors for Drosophila!
38. Functional Consequences of Mutation
(See Fig. 4.1)
• A wild type phenotype is produced when an organism has
two copies of the wild type allele
• Mutant alleles can be:
• Gain-of-function, in which the gene product acquires a
new function or express increased wild type activity
• Loss-of-function, in which there is a significant
decrease or complete loss of functional gene product
40. Dominant Negative Mutations
• Multimeric proteins, composed of two or more polypeptides
that join together to form a functional protein are particularly
subject to dominant negative mutations
• These are negative mutations due to their “spoiler” effect on
the protein as a whole