h emophilia matt carmen josue kernizan matt brill january 28 th, 2010 period 6/7

HEMOPHILIA

Matt Carmen

Josue Kernizan

Matt Brill

January 28th , 2010

Period 6/7

SUMMARY OF HEMOPHILIA

Hemophilia is a disorder of your blood-clotting system

Clotting- the process by which your blood changes from a liquid to a solid state this is used to stop bleeding

Painful, lasting headache Repeated vomiting Extreme fatigue Neck pain Double vision Nosebleeds with no obvious cause Tightness in your joints

WHAT CHROMOSOME HEMOPHILIA IS LOCATED ON?

The gene that causes hemophilia A or B is located on the X chromosome

Mode of Inheritance

Acquired when a clotting gene is mutated, located in the x- chromosome.

Caused by autosomal recessive genes- the disease travels via the autosomes.

Hemophilia is an autosomal recessive disorder. Only men can get hemophilia A and B, because women have 2 x-chromosomes, so men, with an X and a Y recessive chromosome, can only contract this disorder.

Hemophilia C occurs when two reccisive X chromosomes are combined.

ALLELES An individual inherits two alleles for each

gene, one from each parent. Recessive is a quality found in the

relationship between two versions of a gene. If the alleles are different, the dominant allele will be expressed, while the effect of the other allele, called recessive, is masked.

RR=Dominant rr=recessive Rr=dominant There are many more X-linked traits than

there are Y-linked traits.

XH

Xh

XH

Y

XHXH XHY

XHXh XhY

A PHENOMINAL EXAMPLE OF A PUNNET SQUARE.

XhXH

XH

Xh

XHXH XHXh

XhXHXhXh

Ratios and Percents of Hemophelia

Ratios- homozygous dominant : heterozygous dominant : homozygous recessive

1 : 2 : 1 1 XHXH : 2 XHXh : 1 XhXh

Percentages- homozygous dominant : heterozygous dominant : homozygous recessive

25% : 50% : 25% 25% XHXH : 50% XHXh : 25% XhXh

XhXH

XH

Xh

XHXH XHXh

XHXhXhXh

What do these genes mean?

The H genes, both dominant and recessive, are blood clotting genes.

Phenotype: XHXH – blood clotsXHXh - blood clots ( carrier)XhXh- blood doesn’t clotGenotypes:XHXH- Homozygous dominant (blood clots)

XHXh – Heterozygous dominant (blood clots, carrier)

XhXh – Homozygous recessive (blood doesn’t clot)

Xh

XHXh

XH

XH

Xh

XHXH XHXh

XhXh

Probabilities of Geno/Phenotypes

Phenotype Ratio- 3 blood clot: 1 non-blood clotPercent- 75% blood clot:25% non-blood clot

Genotype Ratio- 1 XHXH : 2 XHXh : 1 XhXh

Percent- 25% XHXH : 50% XHXh : 25% XhXh

Xh

XHXh

XH

XH

Xh

XHXH XHXh

XhXh

Student Practice

Phenotype:Ratio:

Percentage:

Genotype:Ratio:

Percentage:

XH

XH

Y

Xh

XHXH XHY

XHXh XhY

3:1

75%:25%

1:2:1

25%:50%:25%

3 Generation Pedigree

Hemophilic Male

Female Carrier

Normal Female

Normal Male

Student Practice

1. What shape shows a hemophiliac

2. How many people in the third generation have hemophilia

3. What gender must the dark rectangles be?

Hemophilic Male

Female Carrier

Normal Female

Normal Male