Human GeneticsMonica Starbinski

Greer Manton

Sydney Gilbert

Period 2

Pedigrees

Monica Starbinski

Key – -Male(affected)

- Male (normal)

-Female (affected)

- Female (normal)

- Heterozygous for recessive allele

Generation 1

Generation 2

Generation 3

Autosomal Recessive Disorders

Tay-Sachs Disease

Cystic Fibrosis

Albinism

The disorder is present.

Phenotype ratio –1 has disease : 3 do notPercentage – 25% have disease, 75% dont

Genotype ratio –1 AA : 2 Aa : 1 aaPercentage – 25% AA, 50% Aa ,

25% aa

Autosomal Dominant Disorders / Traits

Huntington’s Disease

Widow’s Peak Hairline

Free/Hanging Earlobes

Phenotype ratio –3 have disease : 1 does notPercentage – 75% have disease, 25% dont

Genotype ratio –1 GG : 2 Gg : 1 ggPercentage – 25% GG, 50% Gg,

25% gg

The disorder is present.

Current Event on Human Genetics

http://www.sciencenews.org/view/generic/id/59938/title/Tracing_Jewish_roots

Greer Manton

CodominanceGenotype Ratio:1 A1A1 : 2 A1A2 : 1 A2A2Percentage:25% A1A1, 50% A1A2,

25% A2A2

Phenotype Ratio:1 Purple : 2 Red : 1

YellowPercentage:25% Purple, 50% Red,

25% Yellow

Homozygous

Heterozygous

Roan Cattle

RR’ FlowerR’ R

R

R’

RR’

RR

R’R’ RR’

Greer Manton

Multiple AllelesGenotype Ratio:1 TTWW : 3 TTWw, 2 TtWW

: 4 TtWw, 2 Ttww : 1 ttWW, 2 ttWw : 1 ttww

Percentage: 6.25% TTWW, 18.75%

TTWw, 12.5% TtWW, 25% TtWw, 12.5% Ttww, 6.25% ttWW, 12.5% ttWw, 6.25% ttww

TtWw x TTWw

Dihybrid

Haemolytic Anaemia

Greer Manton

Sex-linked Disorders

Down SyndromeColor Blindness Hemophilia

XX XY

XX’ X’Y

X Y

X

X’

Genotype Ratio: 1 XX; 1 XY; 1 XX’; 1 X’Y

Phenotype Percentage: 25% XX; 25% XY;25% XX’; 25% X’Y

Sydney Gilbert

Questions!

1: What is the chance that a mother can pass on the sex linked gene of color blindness?

2: What is bound to happen when a pink flower is crossed with a white flower and results in codominance?

3: If you are albino, what type of dominance do you have?

4: If you possess attached earlobes, what type of dominance is it?

Sydney Gilbert

Sydney Gilbert