handout no. 1 for genetics students

GeneticsGenetics

Study ofStudy of heredityheredity andand variationvariation

among members of a species among members of a species and/orand/or

among organismsamong organisms HeredityHeredity connotesconnotes similarities;similarities;

VariationVariation meansmeans differencesdifferences Applies to living or formerly living Applies to living or formerly living

members of a species or taxonmembers of a species or taxon

Heredity and variationHeredity and variation

Heredity and VariationHeredity and Variation

Heredity and variationHeredity and variation

Heredity and VariationHeredity and Variation

Scope of GeneticsScope of Genetics

Genes

DNA

Chromosomes

Individuals

Population

Family

Karyotype

Levels of Genetic Studies


DNA level and gene level

Scope of Genetics: Chromosome levelScope of Genetics: Chromosome level


KaryotypeKaryotype= the chromosome = the chromosome

complement of a cell complement of a cell or speciesor species

= often represented by = often represented by an arrangement of an arrangement of metaphase metaphase chromosomes chromosomes according to their according to their lengths and the lengths and the position of their position of their centromerescentromeres

Karyotype level

Scope of GeneticsScope of Genetics Karyotype levelKaryotype level

Scopeof GeneticsScopeof Genetics

Karyotype levelKaryotype level

Scope of Genetics: Family LevelScope of Genetics: Family Level

Scope of Genetics: Population LevelScope of Genetics: Population Level

Scope of Genetics:Scope of Genetics:Topics studied in genetics overlap directly withTopics studied in genetics overlap directly with

Areas of GeneticsAreas of Genetics

Three general areasThree general areas::

1. Classical Genetics1. Classical Genetics

2. Molecular Genetics2. Molecular Genetics

3. Population and Evolutionary 3. Population and Evolutionary

GeneticsGenetics


Classical GeneticsClassical Genetics – – concerned with genes, concerned with genes, mutations, and phenotypes; specifically:mutations, and phenotypes; specifically:

1.1. transmission of genes to the next transmission of genes to the next generation through meiosis;generation through meiosis;

2.2. methods that generate mutations and methods that generate mutations and identify mutants;identify mutants;

3.3. patterns of inheritance to produce a specific patterns of inheritance to produce a specific trait or phenotype.trait or phenotype.


Molecular GeneticsMolecular Genetics

- the study of the structure, replication, and - the study of the structure, replication, and expression of the genetic materialexpression of the genetic material

- also includes the methods involved in - also includes the methods involved in manipulating the expression and analysis of manipulating the expression and analysis of the genetic material (recombinant DNA the genetic material (recombinant DNA technology and genomics)technology and genomics)


Population and Evolutionary Population and Evolutionary GeneticsGenetics

- - study of the mechanisms that result study of the mechanisms that result in changes in allele frequencies in in changes in allele frequencies in populations over time and the populations over time and the consequencies of those changesconsequencies of those changes

Fields of Genetic Fields of Genetic Studies Studies ((subdivisions wherein a geneticist can become an authority)subdivisions wherein a geneticist can become an authority)

1.1. CytogeneticsCytogenetics – – merging of cytology with merging of cytology with geneticsgenetics

2. 2. Biochemical geneticsBiochemical genetics - - merging of merging of genetics with biochemistrygenetics with biochemistry

3.3. Molecular geneticsMolecular genetics – – merging of genetics merging of genetics with molecular biologywith molecular biology

4. 4. Population geneticsPopulation genetics – – study of genetics study of genetics at the population levelat the population level

5.5. Microbial geneticsMicrobial genetics – – study of genetics in study of genetics in microorganisms such as bacterial geneticsmicroorganisms such as bacterial genetics

6. 6. Human geneticsHuman genetics –– study of genetics in study of genetics in human beingshuman beings

Fields of Genetic StudiesFields of Genetic Studies

7. 7. Quantitative GeneticsQuantitative Genetics – the study of heredity and – the study of heredity and variation of measurable traits (height, weight, color variation of measurable traits (height, weight, color intensity, etc.) that depend on the cumulative action of intensity, etc.) that depend on the cumulative action of many genes, each producing a small effect on the many genes, each producing a small effect on the phenotype; such traits are analyzed and characterized phenotype; such traits are analyzed and characterized using statistical methodsusing statistical methods

8. 8. Evolutionary GeneticsEvolutionary Genetics – deals with genetic basis of – deals with genetic basis of evolutionary changes and relationshipsevolutionary changes and relationships

9. 9. Medical geneticsMedical genetics – deals with illnesses or diseases – deals with illnesses or diseases that have a genetic cause or influenced by genesthat have a genetic cause or influenced by genes

10. 10. Developmental GeneticsDevelopmental Genetics – deals with the genetic – deals with the genetic basis of developmental stages and/or defectsbasis of developmental stages and/or defects

Fields of Genetic StudiesFields of Genetic Studies

11. 11. Behavioral GeneticsBehavioral Genetics – deals with the genetic – deals with the genetic basis of behavior with/without environmental basis of behavior with/without environmental

influenceinfluence

12. 12. ImmunogeneticsImmunogenetics – deals with the genetics of – deals with the genetics of

the immune responsethe immune response

13. 13. Agricultural GeneticsAgricultural Genetics – deals with the genetics – deals with the genetics of agricultural cropsof agricultural crops

14. 14. Plant GeneticsPlant Genetics – genetics of plants– genetics of plants

15. 15. Animal Genetics-Animal Genetics- genetics of animalsgenetics of animals

Fields of GeneticsFields of Genetics

16. Conservation Genetics16. Conservation Genetics – the application of – the application of population, quantitative,and evolutionary genetic principles to population, quantitative,and evolutionary genetic principles to preserve groups of organisms; it also provides guidance for the preserve groups of organisms; it also provides guidance for the sustainable use of the earth’s genetic resources to guarantee sustainable use of the earth’s genetic resources to guarantee food security for present and future generationsfood security for present and future generations

17. Ecological Genetics17. Ecological Genetics – the application of quantitative – the application of quantitative genetics in ecology; it is the study of the ecological interactions of genetics in ecology; it is the study of the ecological interactions of organisms with their biotic and abiotic environmentorganisms with their biotic and abiotic environment

Fields of GeneticsFields of Genetics

18. 18. GenomicsGenomics – the analysis of the DNA content – the analysis of the DNA content and gene organization in and between organismsand gene organization in and between organisms

19.19. ProteomicsProteomics – the study of all the proteins – the study of all the proteins expressed by the individual or organismexpressed by the individual or organism

20. Bioinformatics20. Bioinformatics – deals with the comparison and – deals with the comparison and analysis of DNA sequencesanalysis of DNA sequences

History of GeneticsHistory of Genetics

Before 1860: Before 1860: Discovery of the cell Discovery of the cell and the nucleusand the nucleus

Hippocratic school of Hippocratic school of thought into the 18thought into the 18thth century persisted–century persisted– offsprings are preformed offsprings are preformed inside the gametesinside the gametes

History of Genetics: History of Genetics: Before 1860Before 1860

William HarveyWilliam Harvey (1600) – (1600) – substances in the gametes produce substances in the gametes produce the adult structurethe adult structure

Robert HookeRobert Hooke (1665) – (1665) – coined the term cell to describecoined the term cell to describe structures observed in cork under a microscopestructures observed in cork under a microscope

Anton van LeeuwenhoekAnton van Leeuwenhoek (1674-1683) - (1674-1683) - produced simpleproduced simple microscopes; discovered living organisms in rainwatermicroscopes; discovered living organisms in rainwater

Jan PurkinjeJan Purkinje (1830) (1830) –– first described the nucleus within the cellfirst described the nucleus within the cell

Robert BrownRobert Brown (1831) (1831) – coined the term nucleus– coined the term nucleus

Hugo von MohlHugo von Mohl (1835-1839) (1835-1839) – described mitosis in a cell– described mitosis in a cell

Rudolf VirchowRudolf Virchow (1858) – (1858) – summedsummed up the concept of the cell up the concept of the cell theory with “all cells come from pre-existing cells”theory with “all cells come from pre-existing cells”

History of GeneticsHistory of Genetics1860-1900: 1860-1900: Mendelian Traits and Observation Mendelian Traits and Observation

of Chromosomesof Chromosomes Gregor MendelGregor Mendel published his work in 1866 wherein he published his work in 1866 wherein he

described the statistical patterns of heritable phenotypes and described the statistical patterns of heritable phenotypes and proposed the theory that factors (genes) in the germ cells proposed the theory that factors (genes) in the germ cells formed the basis of inheritance patternsformed the basis of inheritance patterns

Hugo de Vries, Carl Correns, and Erich von TschermakHugo de Vries, Carl Correns, and Erich von Tschermak (1900)(1900) independently duplicated Mendel’s work and Mendel’s work independently duplicated Mendel’s work and Mendel’s work became acceptedbecame accepted

Oscar HertwigOscar Hertwig (1875) (1875) described the fusion of egg and sperm described the fusion of egg and sperm to form the zygoteto form the zygote

Walther Flemming (1879-1885)Walther Flemming (1879-1885) – used aniline dyes to view – used aniline dyes to view and describe chromosomes during meiosisand describe chromosomes during meiosis

August Weismann (1885)August Weismann (1885) – stated that the inheritance of traits – stated that the inheritance of traits is based exclusively in the nucleusis based exclusively in the nucleus

Heinrich WaldeyerHeinrich Waldeyer (1888) (1888) first used the term first used the term chromosomechromosome

Hertwig and BoveriHertwig and Boveri (1890) (1890) described the process of meiosis in described the process of meiosis in detaildetail

History of GeneticsHistory of Genetics1900-19441900-1944: : Start of modern genetics as a field of Start of modern genetics as a field of

sciencescience Development of the Chromosome TheoryDevelopment of the Chromosome Theory - - stated that stated that

chromosomes are linear arrays of genes that contained the chromosomes are linear arrays of genes that contained the genetic information required by living organismsgenetic information required by living organisms

Walter Sutton (1902)Walter Sutton (1902) – – hypothesized that the behavior of hypothesized that the behavior of chromosomes during meiosis explained Mendel’s rules of chromosomes during meiosis explained Mendel’s rules of inheritanceinheritance

T. H. Morgan, N. M. Stevens and B. Mawr (1905T. H. Morgan, N. M. Stevens and B. Mawr (1905)–)– investigated investigated sex detemination in mealworms and dicovered X and Y sex detemination in mealworms and dicovered X and Y chromosomeschromosomes

T. H Morgan (1911T. H Morgan (1911)) – demonstrated that genes producing white – demonstrated that genes producing white eyes, yellow body and miniature wings in eyes, yellow body and miniature wings in DrosophilaDrosophila are are located on the X chromosome located on the X chromosome

Alfred Sturtevant (1913)Alfred Sturtevant (1913) – used Drosophila to create the first – used Drosophila to create the first genetic map which demonstrated that genes existed in a linear genetic map which demonstrated that genes existed in a linear order on chromosomesorder on chromosomes

History of GeneticsHistory of Genetics Calvin Bridges and T.H. Morgan (1914)Calvin Bridges and T.H. Morgan (1914) – – described described

nondisjunction of nondisjunction of DrosophilaDrosophila sex chromosomes to prove the sex chromosomes to prove the chromosomal theory of inheritancechromosomal theory of inheritance

Lewis Stadler and Hermann Muller (1927)Lewis Stadler and Hermann Muller (1927) – – showed that genes showed that genes can be mutated artificially by X-rayscan be mutated artificially by X-rays

William BatesonWilliam Bateson – – first coined the term F1, F2, heterozygote, first coined the term F1, F2, heterozygote, homozygote and allele in 1902. He created the term genetics in homozygote and allele in 1902. He created the term genetics in 1905.1905.

Wilhelm Johannsen (1909) –Wilhelm Johannsen (1909) – introduced the terms genotype, introduced the terms genotype, phenotype and genephenotype and gene

R.A. Fisher, Sewall Wright, and J.B.S. HaldaneR.A. Fisher, Sewall Wright, and J.B.S. Haldane (between 1930 (between 1930 and 1932) –and 1932) – developed the algebraic foundations for our developed the algebraic foundations for our understanding of the process of evolutionunderstanding of the process of evolution

Salvador Luria and Max Delbruck (1943) –Salvador Luria and Max Delbruck (1943) – demonstrated that demonstrated that bacteria have genetic systems and phenotypes that could be bacteria have genetic systems and phenotypes that could be studiedstudied

History of GeneticsHistory of Genetics

1944 to present1944 to present:: Discovery of DNA, RNA and era of Discovery of DNA, RNA and era of molecular geneticsmolecular genetics

Oswald Avery and colleagues (1944)Oswald Avery and colleagues (1944) and and Alfred Hershey and Alfred Hershey and Martha Chase (1952)Martha Chase (1952) – – showed conclusively in their showed conclusively in their experiments that DNA or deoxyribonucleic acid was the experiments that DNA or deoxyribonucleic acid was the genetic materialgenetic material

James Watson and Francis Crick (1953)James Watson and Francis Crick (1953) – – worked out the DNA worked out the DNA structure based on experimental datastructure based on experimental data

Werner Arber, Hamilton Smith, Daniel Nathans and colleaguesWerner Arber, Hamilton Smith, Daniel Nathans and colleagues (between 1968 and 1973(between 1968 and 1973) –) – discovered and described discovered and described restriction endonucleases, the enzymes that can cut DNA at restriction endonucleases, the enzymes that can cut DNA at specific sitesspecific sites

Paul Berg (1972)Paul Berg (1972) – – first to construct a recombinant DNA first to construct a recombinant DNA molecule containing parts of DNA from different speciesmolecule containing parts of DNA from different species

Since 1972Since 1972,, many scientists have cloned numerous genes many scientists have cloned numerous genes including genes that correspond to inherited diseasesincluding genes that correspond to inherited diseases

History of GeneticsHistory of Genetics 1995 –1995 – HaemophilusHaemophilus influenza influenza was the first organism to have was the first organism to have

its genome sequencedits genome sequenced 2001 –2001 – human genome was sequenced and publishedhuman genome was sequenced and published September 2007-September 2007- 634 different organisms have had their 634 different organisms have had their

complete genomes sequenced and publishedcomplete genomes sequenced and published 1997 –1997 – first transgenic cow, named Rosie, was createdfirst transgenic cow, named Rosie, was created 1996 –1996 – first mammal was cloned, a sheep named Dollyfirst mammal was cloned, a sheep named Dolly

Since thenSince then, pigs, mules, cattle, cats and dogs are some, pigs, mules, cattle, cats and dogs are some of the of the animals that have been cloned; cloned animals can be used for animals that have been cloned; cloned animals can be used for the study of specific diseases, the expression of the study of specific diseases, the expression of pharmaceuticals, and the isolation of tissues and organs for pharmaceuticals, and the isolation of tissues and organs for human use. human use.

Dolly

Applications of GeneticsApplications of Genetics

1.1. Genetic improvement of crop Genetic improvement of crop plants or plant breedingplants or plant breeding

- planned hybridization or breeding work has - planned hybridization or breeding work has developed high-yielding varieties ofdeveloped high-yielding varieties of

crop plants with specific desirable traits crop plants with specific desirable traits

Applications of Genetics: Applications of Genetics: Plant BreedingPlant Breeding

Applications of Genetics: Plant BreedingApplications of Genetics: Plant Breeding

Applications of GeneticsApplications of Genetics:: Plant BreedingPlant Breeding

Plant BreedingPlant Breeding


2. Genetic 2. Genetic improvement improvement of animals of animals

(animal (animal breeding)breeding)

- specific - specific animal breeds animal breeds or genotypes or genotypes have been have been produced for produced for specific specific purposespurposes

Animal breedingAnimal breeding

Application of geneticsApplication of genetics

Animal breedingAnimal breeding


3. In the field of 3. In the field of

medicine medicine Determination or Determination or

study of genetic study of genetic diseases in diseases in individuals either individuals either for clinical for clinical diagnosis or for diagnosis or for treatmenttreatment

- these are diverse - these are diverse group of disordersgroup of disorders

caused by caused by mutations and mutations and chromosome chromosome abnormalities abnormalities

Genetics in the medical fieldGenetics in the medical field

Genetics in medicineGenetics in medicine

In Medicine

Turner Syndrome 2n=45, X0Karyotype

Application of Genetics in MedicineApplication of Genetics in Medicine


5. Genotoxicity testing5. Genotoxicity testing GenotoxicityGenotoxicity refers to the detection of agents refers to the detection of agents

that will damage DNA and hence cause mutations.that will damage DNA and hence cause mutations.

Commercial tests can use animal experiments, but Commercial tests can use animal experiments, but

these are largely replaced by these are largely replaced by in vitro in vitro systems utilizing systems utilizing bacteria or animal cells in tissue culture. bacteria or animal cells in tissue culture.

The tests used are The tests used are Ames testAmes test, , cell line mutationcell line mutation teststests, , and and cytogenetic tests.cytogenetic tests.


6. Gene therapy6. Gene therapy – treatment of a genetic disorder– treatment of a genetic disorder

by the introduction of functional copies of the gene by the introduction of functional copies of the gene responsible for the disorder/disease into the patient.responsible for the disorder/disease into the patient. Two types:Two types:

1. 1. in vivoin vivo therapy therapy – carried out by introducing functional – carried out by introducing functional copies of the gene into the patient and hoping that the genes copies of the gene into the patient and hoping that the genes will find an appropriate target cell to cure the disorder/dissease.will find an appropriate target cell to cure the disorder/dissease.

2. 2. ex vivoex vivo therapy therapy – cells are removed from the patient, – cells are removed from the patient, manipulated in cell culture, and then returned to the patient.manipulated in cell culture, and then returned to the patient.


7. Genetic counseling7. Genetic counseling

- the geneticist studies the genetic - the geneticist studies the genetic background of couples who want to have background of couples who want to have children and then advise them on the children and then advise them on the probabilities of their having children with probabilities of their having children with specific inherited traits; the prospective specific inherited traits; the prospective parents can then decide whether to proceed parents can then decide whether to proceed with a pregnancy or not, especially if prenatal with a pregnancy or not, especially if prenatal testing of the unborn has also been done.testing of the unborn has also been done.

Application of Genetics: Application of Genetics: Genetic CounselingGenetic Counseling

ExampleExample

Genetic counselingGenetic counseling


8. Legal applications/court cases8. Legal applications/court cases

- - genetic data can be used as evidence in genetic data can be used as evidence in legal battles concerning parentage and also legal battles concerning parentage and also as forensic evidence in the scenes of as forensic evidence in the scenes of crimescrimes

- for example, - for example, blood typesblood types is an inherited is an inherited trait that can provide evidence of trait that can provide evidence of parentage; parentage; DNA fingerprintingDNA fingerprinting is another is another

DNA FingerprintingDNA Fingerprinting


9. Control of pests9. Control of pests - the - the sterile-insect-technique or SITsterile-insect-technique or SIT is a method of is a method of

producing genetically sterile males then followed by producing genetically sterile males then followed by the release of these genetically sterile males in the the release of these genetically sterile males in the insect population to compete with normal males.insect population to compete with normal males.

(genetically)(genetically) sterile malessterile males X X fertile femalesfertile females -- -- nonviable eggs nonviable eggs fertile malesfertile males X X fertile femalesfertile females -- -- viable eggs viable eggs


10. Forensic science10. Forensic science

- - forensic DNA samples from the scene of a forensic DNA samples from the scene of a crime can be crime can be amplified amplified (multiplied or (multiplied or reproduced) millions of times by reproduced) millions of times by PCRPCR ((polymerase chain reactionpolymerase chain reaction))

- the amplified DNA sequences can be - the amplified DNA sequences can be analyzed and used to identify individuals who analyzed and used to identify individuals who are present in the scene of the crime (are present in the scene of the crime (DNA DNA fingerprintingfingerprinting))

Forensic scienceForensic science


11. Analysis of DNA sequences amplified by PCR11. Analysis of DNA sequences amplified by PCR

- also used in tissue typing to match organ - also used in tissue typing to match organ donors with recipientsdonors with recipients

- also used in anthropology to study the - also used in anthropology to study the origins or races of peopleorigins or races of people


11. Genetic engineering11. Genetic engineering

- this field of research uses - this field of research uses gene transfergene transfer

techniquestechniques to produce to produce recombinantrecombinant proteinsproteins and and genetically modifiedgenetically modified organismsorganisms

- the commercial application of these - the commercial application of these

techniques has led to the development of techniques has led to the development of

the the biotechnology industrybiotechnology industry

Genetic EngineeringGenetic Engineering

Genetic Engineering: GMO rice

handout no. 1 for genetics students

Documents

animal genetics genetics

developmental genetics

agricultural genetics

medical genetics

conservation genetics

quantitative genetics

behavioral genetics

evolutionary genetics