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