Biology 2250Biology 2250Principles of GeneticsPrinciples of Genetics

Instructors:Instructors:

Dr. Steven M. CarrDr. Steven M. Carr Molecular GeneticsMolecular Genetics

Dr. David J. InnesDr. David J. Innes Mendelian GeneticsMendelian Genetics

Course Web PagesCourse Web Pages

Dr.Innes:Dr.Innes: www.www.munmun.ca/biology/.ca/biology/dinnesdinnes/B2250/B2250.html/B2250/B2250.html

Dr. Carr:Dr. Carr: www.mun.ca/biology/scarr/Bio2250.html www.mun.ca/biology/scarr/Bio2250.html

Text Web Page:Text Web Page: http://www.http://www.whfreemanwhfreeman.com/.com/mgamga//

Virtual Fly:Virtual Fly: http://www.biologylabsonline.com/ http://www.biologylabsonline.com/

Tentative Lecture Dates Tentative Lecture Dates and Topicsand Topics

Carr: Carr: Sept. 8 – Oct. 4Sept. 8 – Oct. 4 Structure and function of DNA and genesStructure and function of DNA and genes

Innes: Innes: Oct. 13 – Nov. 15 Oct. 13 – Nov. 15 Mendelian GeneticsMendelian Genetics

Carr:Carr: Nov. 22 – Dec. 1 Nov. 22 – Dec. 1 Molecular GenomicsMolecular Genomics

Tests: I Oct. 6 (Thurs)Tests: I Oct. 6 (Thurs)

II Nov.17 (Thurs)II Nov.17 (Thurs)

Weekly Online QuizzesWeekly Online Quizzes

MarksMarksOct. 14 Example Quiz 2** Oct. 14 Example Quiz 2** for logging in for logging in

Oct. 21 Quiz 1 2Oct. 21 Quiz 1 2

Oct. 28 Quiz 2 2Oct. 28 Quiz 2 2

Nov. 4 Quiz 3 2Nov. 4 Quiz 3 2

Nov. 10 Quiz 4 2Nov. 10 Quiz 4 2

WebCT QuizzesWebCT Quizzes

Log in: http://webct.mun.ca:8900/Log in: http://webct.mun.ca:8900/

Webct Webct quizzesquizzes

Course GoalsCourse Goals

• Understanding of basic geneticsUnderstanding of basic genetics

• Solve problemsSolve problems

• Think and think criticallyThink and think critically

• Contribute to a discussion on Contribute to a discussion on

current issues in geneticscurrent issues in genetics

(GMO, gene therapy…)(GMO, gene therapy…)

What is Genetics ?What is Genetics ?- Genetics is the study of heredity and variation- Genetics is the study of heredity and variation

- Examples of genetic variation (within species)- Examples of genetic variation (within species)

1. Domesticated species1. Domesticated species

2. Human genetics2. Human genetics

3. Natural Populations3. Natural Populations

Genetic variation Genetic variation Phenotypic variation Phenotypic variation

Molecular genetic variationMolecular genetic variation

Cultivated varietiesCultivated varieties

Animal BreedsAnimal Breeds

Human GeneticHuman Genetic

VariationVariation

Natural Natural PopulationsPopulations

Which Which suspect suspect matches matches blood stain ?blood stain ?

Molecular Genetic VariationMolecular Genetic Variation

DNA FingerprintDNA Fingerprint

DNA SequenceDNA Sequence

Protein variationProtein variation

Subareas of GeneticsSubareas of Genetics

cytogeneticscytogenetics

molecular geneticsmolecular genetics

human geneticshuman genetics

population geneticspopulation genetics

quantitative geneticsquantitative genetics

developmental geneticsdevelopmental genetics

immunogeneticsimmunogenetics

etc. etc.etc. etc.

Genetic JournalsGenetic JournalsAmerican Journal of Medical Genetics Clinical GeneticsAmerican Journal of Medical Genetics Clinical Genetics

Developmental Genetics Human Molecular GeneticsDevelopmental Genetics Human Molecular Genetics

Genetics European J. of Human GeneticsGenetics European J. of Human Genetics

Genetics Selection Evolution Nature GeneticsGenetics Selection Evolution Nature Genetics

Genetika Fungal Genetics and BiologyGenetika Fungal Genetics and Biology

Genome Cancer Genetics and CytogeneticsGenome Cancer Genetics and Cytogenetics

Genomics American J. Human Genetics Genomics American J. Human Genetics

Heredity Annals of Human GeneticsHeredity Annals of Human Genetics

Hereditas Opthalmic GeneticsHereditas Opthalmic Genetics

Japanese Journal of Human Genetics Human GeneticsJapanese Journal of Human Genetics Human Genetics

Journal of Heredity Current GeneticsJournal of Heredity Current Genetics

Molecular Biology and Evolution Animal GeneticsMolecular Biology and Evolution Animal Genetics

Molecular Ecology Brazilian J. GeneticsMolecular Ecology Brazilian J. Genetics

Molecular and General Genetics Biochemical GeneticsMolecular and General Genetics Biochemical Genetics

Theoretical and Applied Genetics J. of Medical GeneticsTheoretical and Applied Genetics J. of Medical Genetics

Trends in Genetics (http://www.trends.com/tig/default.htm)Trends in Genetics (http://www.trends.com/tig/default.htm)

History of GeneticsHistory of Genetics

• Domestication of animalsDomestication of animals

• Cultivation of plantsCultivation of plants

Historical NotesHistorical Notes

1953 1953 J. D.J. D. Watson and F. Crick(*)Watson and F. Crick(*)

DNA StructureDNA Structure

http://www.sil.si.edu/Exhibitions/Science-and-the-http://www.sil.si.edu/Exhibitions/Science-and-the-Artists-Book/bioc.htmArtists-Book/bioc.htm

Advances in GeneticsAdvances in Genetics

• Human Genome Sequence Human Genome Sequence

http://www.hgsc.bcm.tmc.edu/http://www.hgsc.bcm.tmc.edu/

• Drosophila Drosophila Genome sequenceGenome sequence

http://flybase.bio.indiana.edu/http://flybase.bio.indiana.edu/

• Other organsims:Other organsims:

http://daphnia.cgb.indiana.edu/http://daphnia.cgb.indiana.edu/

http://www.jgi.doe.gov/ http://www.jgi.doe.gov/

Genetic InformationGenetic Information

Online Mendelian Inhertitance in Man (OMIM)Online Mendelian Inhertitance in Man (OMIM)

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=OMIMdb=OMIM

Online Mendelian Inhertiance in Animals (OMIA)Online Mendelian Inhertiance in Animals (OMIA)

http://omia.angis.org.au/http://omia.angis.org.au/

Ethical Issues in GeneticsEthical Issues in Genetics

Ethical Issues in GeneticsEthical Issues in Genetics

• Genetically modified organisms (GMO)Genetically modified organisms (GMO)

• Gene therapy (Parkinson’s) Gene therapy (Parkinson’s) http://hdlighthouse.org/research/genetherapy/updhttp://hdlighthouse.org/research/genetherapy/updates/0053parkinson.phtmlates/0053parkinson.phtml

• Designer genesDesigner genes

• Data banks of DNA finger prints (criminals?)Data banks of DNA finger prints (criminals?)

• Cloning (Stem cell research)Cloning (Stem cell research)

CloningCloning19971997

19981998

1999 - 20021999 - 2002

DollyDolly““An udder way of An udder way of making lambs”making lambs”

nucleusnucleus fosterfoster eggegg

SheepSheep

MiceMice

PigPig

GoatGoat

CowCow

“Cc” copy cat

Genetics in the NewsGenetics in the News

Basic Concepts of GeneticsBasic Concepts of Genetics(Chapter 1)(Chapter 1)

NucleusNucleus contains genetic material contains genetic material

DNADNA genetic material genetic material

4 bases (nucleotides G, C, A, T) 4 bases (nucleotides G, C, A, T)

GeneGene functional unit of heredity functional unit of heredity

sequence of 4 nucleotidessequence of 4 nucleotides

ChromosomeChromosome linear DNA molecule linear DNA molecule

Pairs of Chromosomes Pairs of Chromosomes (maternal, paternal)(maternal, paternal)

Two sets of chromosomes: diploidTwo sets of chromosomes: diploid

One set of chromosomes: haploidOne set of chromosomes: haploid

DNA ReplicationDNA Replication

1. Transcription of mRNA from DNA1. Transcription of mRNA from DNA

2. Translation of mRNA: triplet codon2. Translation of mRNA: triplet codon

Amino acid

Gene Expression

Understanding GeneticsUnderstanding Genetics

Relationship between:Relationship between:

GENOTYPE ENVIRONMENT PHENOTYPEGENOTYPE ENVIRONMENT PHENOTYPE

set of genes morphologyset of genes morphology

inherited physiologyinherited physiology

behaviourbehaviour

Interaction of genes and environment

PhenotypeGenotype

Mendelian GeneticsMendelian Genetics

Topics:Topics: - - Transmission of DNA during cell divisionTransmission of DNA during cell division

Mitosis and Meiosis Mitosis and Meiosis (Ch. 4)(Ch. 4)

- Segregation - Segregation (Ch. 5)(Ch. 5)

- Sex linkage - Sex linkage (Ch. 5) (Ch. 5)

- Inheritance and probability - Inheritance and probability (Ch.5)(Ch.5)

- Mendelian genetics in humans- Mendelian genetics in humans

(pedigrees) (pedigrees) (Ch.5)(Ch.5)

- Independent Assortment - Independent Assortment (Ch. 6)(Ch. 6)

- Linkage - Linkage (Ch. 6)(Ch. 6)

- Gene mapping - Gene mapping (Ch. 6)(Ch. 6)

Mendelian GeneticsMendelian Genetics

Topics (cont.):Topics (cont.):

- Tetrad Analysis (mapping in fungi)- Tetrad Analysis (mapping in fungi)

- Extensions to Mendelian Genetics- Extensions to Mendelian Genetics

- Gene mutation- Gene mutation

- Chromosome mutation- Chromosome mutation

- (Quantitative and population genetics)- (Quantitative and population genetics)

Basic Concepts of GeneticsBasic Concepts of Genetics

Cell/nuclear divisionCell/nuclear division

Mitosis (somatic tissue): Mitosis (somatic tissue):

identical cellsidentical cells

Meiosis (germ tissue):Meiosis (germ tissue):

gametes (variation)gametes (variation)

Mendelian Genetics:Mendelian Genetics:ChromosomesChromosomes

Readings:Readings:

Transmission of DNA and cell divisionTransmission of DNA and cell division

- Mitosis and meiosis - Mitosis and meiosis (Ch. 4)(Ch. 4)

pp. 92, 100 – 113pp. 92, 100 – 113

Chromosome Theory of Chromosome Theory of InheritanceInheritance (Ch. 4) (Ch. 4)

- genes organized into chromosomes- genes organized into chromosomes

- correlation: correlation: Genetics & CytologyGenetics & Cytology

- theory can explain the behaviour - theory can explain the behaviour of genes (segregation and of genes (segregation and independent assortment)independent assortment)

Chromosome and DNA Chromosome and DNA ReplicationReplication

1.1. DNA replication results inDNA replication results in

chromosome replicationchromosome replication

2. Nuclear and cell division2. Nuclear and cell division

Haploid (n)

Diploid (2n)

Mitosis

Cell cycle:

S = synthesis

G = “gaps”

2n2n

nn

n = # of chr. in a set

Meiosis

2n2n nn

Animal

eggegg

Polar bodiesPolar bodies

nnnn

Plant

gp = gametophyte

nn

Fungus

Cytological ObservationsCytological Observations

1. 1. Constancy of the number of chromosomConstancy of the number of chromosomeses

2.2. Morphologically similar pairsMorphologically similar pairs (diploid) (diploid)

3. 3. Gametes - contain one set Gametes - contain one set ((haploid)haploid)

2n2n nn

Homologous chromosomesHomologous chromosomes

Two processes of nuclear Two processes of nuclear divisiondivision

1. Mitosis (somatic tissue)1. Mitosis (somatic tissue)

2. Meiosis (germ tissue)2. Meiosis (germ tissue)

MitosisMitosis

1. 1. one parent cell--------> 2 identicalone parent cell--------> 2 identical

daughter cellsdaughter cells

2. same in all organisms2. same in all organisms

3. simple:3. simple:

(a)(a) each chromosome each chromosome

doubles (identical)doubles (identical)

(b)(b) identical halves separate identical halves separate

Four Stages of MitosisFour Stages of Mitosis

1.Prophase1.Prophase

2. Metaphase2. Metaphase

3. Anaphase3. Anaphase

4. Telophase4. Telophase

1. Prophase1. Prophase

- chromosomes condense- chromosomes condense

- 2 chromatids (sister chromatids)- 2 chromatids (sister chromatids)

- centromere- centromere

- nuclear membrane breaks dow- nuclear membrane breaks downn

ChromosomeChromosome

replicationreplication

2. Metaphase2. Metaphase

- chromosomes attach to spindle fibers- chromosomes attach to spindle fibers

- chromosomes migrate to plane between poles- chromosomes migrate to plane between poles

- maximum contraction- maximum contraction: : karyotypekaryotype

- number- number

- centromere position- centromere position

- length- length

Nuclear spindleNuclear spindle

3. Anaphase3. Anaphase

- centromeres divide- centromeres divide

- sister chromatids separate- sister chromatids separate

4. Telophase4. Telophase

- nuclear membrane reforms- nuclear membrane reforms

- spindle disperses- spindle disperses

- cytoplasm divides (cytokinesis)- cytoplasm divides (cytokinesis)

Mitosis:Mitosis: Summary SummaryMitosis:Mitosis:

replicationreplication mitosismitosis

2n = 22n = 2

Mitosis:Mitosis: Summary Summary

replicationreplication mitosismitosis

2n = 42n = 4

Mitosis AnimationMitosis Animation

http://www.whfreeman.com/mga/http://www.whfreeman.com/mga/

Mitosis: Mitosis: LilyLily

Fig. 4-21Fig. 4-21

MeiosisMeiosis(overview)(overview)

diploid (2n) ---------------> haploid (n) gametesdiploid (2n) ---------------> haploid (n) gametes

CChromosome replication hromosome replication once once --------> 2 nuclear --------> 2 nuclear

divisions (meiosis I, divisions (meiosis I, II)II)

one nucleus -------------------> 4 nucleione nucleus -------------------> 4 nuclei

Meiosis I Meiosis IIMeiosis I Meiosis II (reductional) (equational) (reductional) (equational)

Prophase I Prophase IIProphase I Prophase II

Metaphase I Metaphase IIMetaphase I Metaphase II

Anaphase I Anaphase IIAnaphase I Anaphase II

Telophase I Telophase IITelophase I Telophase II

Meiosis I (reductional division)Meiosis I (reductional division)

2n = ?2n = ?Pairing of homologous Pairing of homologous chromosomeschromosomes

Continued Continued

Meiosis II (equational division)Meiosis II (equational division)

4 products 4 products

n = ?n = ?

Meiosis AnimationMeiosis Animation

http://www.whfreeman.com/mga/http://www.whfreeman.com/mga/

Meiosis: Meiosis: Lily Lily pollenpollen

Fig. 4-22Fig. 4-22

Prophase IProphase I

Metaphase IMetaphase I

Anaphase IAnaphase I

Telophase ITelophase I

Prophase IIProphase II

Metaphase IIMetaphase II

Anaphase IIAnaphase II

Telophase IITelophase II

Mitosis MeiosisMitosis Meiosis

somatic cells cells of sexual cyclesomatic cells cells of sexual cycle

one doubling one doublingone doubling one doubling

1 division 1 division 2 cells 2 divisions 2 cells 2 divisions 4 4 cellscells

same amount of DNA ½ amount of DNAsame amount of DNA ½ amount of DNA

Comparison (Fig. 4-24)Comparison (Fig. 4-24)

Mitosis MeiosisMitosis Meiosis

# chrs doesn’t change #chrs. halved# chrs doesn’t change #chrs. halved

No pairing of chr. Synapsis of homologsNo pairing of chr. Synapsis of homologs

Centromeres divide at Centromeres divide at NotNot at anaphase I, at anaphase I,

anaphase but at anaphase IIanaphase but at anaphase II

Conservative VariationConservative Variation

Comparison (continued)Comparison (continued)

Mitosis (n) Mitosis (2n) MeiosisMitosis (n) Mitosis (2n) Meiosis

Fig. 4-20Fig. 4-20

Genetic TerminologyGenetic Terminology

Genes: hereditary elementsGenes: hereditary elements

Alleles: forms of a gene: Alleles: forms of a gene: A , a A , a

b, bb, b++

Genotypes Gene pairsGenotypes Gene pairs

Heterozygote: Heterozygote: Aa bbAa bb++

Homozygotes: Homozygotes: AA aa bb bAA aa bb b+ + bb++

Genes on ChromosomesGenes on ChromosomesExpect behaviour of genes to correlate with Expect behaviour of genes to correlate with the behaviour of chromosomes:the behaviour of chromosomes:

genes chromosomesgenes chromosomes

Diploid (2n) Diploid (2n) AA, Aa, aa pairsAA, Aa, aa pairs

Haploid (n) Haploid (n) A one setA one set

aa

Genes on ChromosomesGenes on Chromosomes

bb+ + bb+ + homozygotehomozygote

Fig. 4-17Fig. 4-17

Genes on ChromosomesGenes on Chromosomes

b bb b+ + heterozygote

b bb b homozygote

Genetic LinksGenetic Linkshttp://www.biology-online.org/tutorials/http://www.biology-online.org/tutorials/2_genetics_evolution.htm2_genetics_evolution.htm

http://www.tokyo-med.ac.jp/genet/mfi-e.htmhttp://www.tokyo-med.ac.jp/genet/mfi-e.htm

http://www.biology.arizona.edu/http://www.biology.arizona.edu/mendelian_genetics/mendelian_genetics.htmlmendelian_genetics/mendelian_genetics.html

http://science.nhmccd.edu/biol/genetics.htmlhttp://science.nhmccd.edu/biol/genetics.html