Genetic Mapping (Chapt. 5)

Basic Principles

Genetic Mapping in Experimental Organisms

Genetic Mapping in Humans

Genes, RFLPs, SNPsMeiosis, Independent Assortment, Linkage and Crossing Over

Two- and Three-point crossesComplementation Analysis

Pedigree Analysis

Fig. 2-8Gametes(haploid cells)

Crossing Over Occurs Between DNA of Homologous Chromosomes

Paternal

Maternal

PairedHomologousChromosomes

A

A

a

a

b

b

B

BaB

Ab

Genetic Map of Drosophila

Fig. 5-14

Drosophila melanogaster (Fruit Fly)

Drosophila melanogaster (Fruit Fly)

Phenotypes• eye color• body color• wing shape• antenna length• bristle pattern

Gene NameRecessive Allele

Dominant Allele (WT)

Curled Wings

Sepia Eyes sese+

Striped Body

Javelin Bristles

cucu+

jvjv+

srsr+

Single Crossover (SCO)

Paternal

Maternal

PairedHomologousChromosomes

Double Crossover (DCO)

PairedHomologousChromosomes

Paternal

Maternal

DCO Products

Pedigree for Inheritance of Blood Type and Nail-Patella Syndrome

GelElectrophoresis

Pedigree for Mapping of HD and a DNA Marker

I

GelElectrophoresis

I

II

Pedigree for Mapping of HD and a DNA Marker

February 2007

1168 Family Pedigrees with at least two individuals with Autism Spectrum Disorder

M LASD

~ 2 cM

orf1 orf2 orf3 orf4

~ 500,000 bp

Band11q13

Chromosome 11

Neurexin Proteins

Population Genetics (Chapter 27)

Mendelian Genetics Applied to Populations

The Hardy-Weinberg Equation (p2 + 2pq + q2)

Test populations for microevolutionMutation rate in humansEstimate frequency of carriers for recessive genetic disordersAssess effect of natural selection on microevolutionAssess effect of inbreedingDNA Profiling (“DNA fingerprinting”)

HIV-1 Structure

(Gp120)

HIV Infection Pathway

HIV-1

Gp120

Cytosol

Extra-cellularSpace

Membrane

CCR5

CD4

HIV Infection Pathway

Protein encodedby CCR5-1 allele(CCR5-1 / CCR5-1 or CCR5-1 / CCR5-∆32)

HIV-1

Gp120

Cytosol

Extra-cellularSpace

Membrane

CCR5

CD4

CCR5 RFLP

CCR5-1

CCR5-∆32

CCR5 Genotype Analysis

Fig. 25-3

CCR5-∆32 Allele Frequency

Fig. 25-4

Assumptions of the Hardy-Weinberg Equation

1. Individuals of all genotypes have equal rates of survival and reproductive success (no selection).

2. No new alleles are created or converted from one allele toanother by mutation.

3. Individuals do not migrate into or out of the population(no gene flow).

4. The population is infinitely large (no genetic drift).

5. Individuals in the population mate randomly (no inbreeding)

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Fibroblast Growth Factor 3 (FGFR3) Receptor

GA

C(Gly to Arg)Achondroplasia Mutations:

FGFR3 Signal Transduction Pathways

DELAYED LYSOSOMAL DEGREDATION

FGFR3 Signal Transduction Pathways

Fig. 27-7

Effect of Selection on Allele Frequency

Fig. 27-8

Changes in CCR5-∆32 Allele Frequency

VNTR-DVNTR-CVNTR-B VNTR-E VNTR-FVNTR-A

Chromosome 7

GTCTAG GTCTAG GTCTAG GTCTAG CAGATC CAGATC CAGATC CAGATC

Tandem Repeat Locus

(a.k.a VNTR, STR, Microsatellite)

VNTR-DVNTR-CVNTR-B VNTR-E VNTR-FVNTR-A

7M

7P

GTCTAG GTCTAG GTCTAGCAGATC CAGATC CAGATC

GTCTAG GTCTAG GTCTAG GTCTAG CAGATC CAGATC CAGATC CAGATC

7M

7P

Fig. 22-27

RFLP Analysis of VNTR Loci