Genetic Disorders

Recessive Disorders

Homozygous Dominant: 2 healthy genes;

healthy

Homozygous Recessive: 2 disease

causing genes; have the disease

Heterozygous: 1 healthy gene & 1 disease

causing gene; carrier of disease but

healthy

Sickle Cell Anemia Abnormal shaped Hemoglobin molecules

Poor Blood Circulation

Recessive Trait

Carriers and diseased are immune to MALARIA

Healthy Lung vs. Cystic Fibrosis

Cystic Fibrosis

Defective transport protein

Mucus clogs the organs, most commonly lungs

Recessive trait

Carriers are immune to TYPHOID FEVER: digestive infection of the middle ages

Huntington's Disease

Brain cell inhibitor

Gradual decay of

the brain tissue

No effects until

middle age

Sex-Linked Disorders

Carried on the X-chromosome

Women can be healthy (XX), carriers

(XHX), or diseased (XHXH)

Men can be healthy (XY) or diseased (XHY)

Color Blindness

Pattern Baldness

Hemophilia

Color Blind

Hemophilia Defective

clotting

protein

Blood does

not clot

Sex-Linked

Recessive

Heterozygous

(carrier) XHX

Sex-Linked Diseases In humans hemophilia is a sex-linked

recessive gene. If the mother is heterozygous for the disease, and the father does not have the gene, what will be the ratios/percentages of genotypes & phenotypes.

Parents

Genotype

Ratios/Percents

= 1:4 =

Phenotypes

Ratios/Percents

= 1:4 = XH

Y

X

X

XHX

XY XHY

XX

25%

XX XHY

= 1:4 =

= 1:4 = 25% 25 %

25%

= 1:4 =

25%

Healthy = XY

XHX

XY = 1:4 =

25 %

Carrier

Female

Healthy

Female

Diseased

Male

Healthy

Male = 1:4 =

= 1:4 = 25%

25%

Genetic Counseling

Medical guidance that informs people of

their genotype

Uses pedigrees, Punnet squares, and

more advanced models to calculate

probable offspring