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Anthony Triplin Steve Jean Jude Saint-Jean February 1, 2010 Period:3. Hemophilia . Hemophilia. Blood does not clot as quickly Most common in males Also known as Christmas disease Double vision, repeated vomiting, extreme fatigue Only males get type A and B Females get type C
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Anthony Triplin Steve Jean Jude Saint-Jean February 1, 2010 Period:3 Hemophilia
Hemophilia • Blood does not clot as quickly • Most common in males • Also known as Christmas disease • Double vision, repeated vomiting, extreme fatigue • Only males get type A and B • Females get type C • Type C less common
Location of Hemophilia • Located on X chromosome
Mode of Inheritance • Hemophilia is sex linked/ x-linked • Can only be passed down on X chromosome • Hemophilia A ( 1 in 10,000 male births, 1 in 100,000,000 female births)
Alleles • Two alleles for each gene • Half from your mom and half from your dad • A capital letter for dominant allele and a lower-case letter for the recessive allele • Dominant allele takes over a recessive allele • Recessive produces only when its paired allele is identical • A X-linked dominant chromosome is represented as XH • A X-linked recessive chromosome is represented as Xh
Hemophilia Punnett Squares XH Y • Punnett squares are used to show the probability of receiving a genetic disorder from a parent. XH XHXH XHY Homozygous Dominant XHXh XhY Xh Xh Y Xh Y XH XHXh XHY XH XHXh XHY XH XHXh XHY XhXh XhY Xh Male w/ hemophilia and female non-carrier Male w/ hemophilia and female carrier Normal Male and female carrier Heterozygous Dominant Homozygous Recessive
Punnett Square Probability Ratios: 1 : 1 : 1 : 1 1 XHXH: 1XHXh:1XHY:1XhY Percentages: 25% : 25% : 25% : 25% 25%XHXH : 25% XHXh : 25%XHY : 25%XhY XH Y XH XHXH XHY XHXh XhY Xh Normal Male and female carrier
Punnett Squares Genotypes and Phenotypes XH Y • What do the letters mean ? • Uppercase letters represent dominant genes • Lowercase letters represent recessive genes • H is the dominant allele • h is are the recessive allele XH XHXH XHY XHXh XhY Xh Phenotype/What We See XHXH = Non Carrier XHXh = Carrier XHY= Normal XhY= Hemophilia Normal Male and female carrier Genotype/What Is In Our Genes XHXH is the Homozygous dominant XHXh is the Heterozygous dominant XhYis the Homozygous recessive
Genotype/Phenotype Probability • Phenotype= The observable characteristic of an organism (Expression of genes) • -Ratios- 1 XHXH: 1 XHXh: 1XHY: 1XhY • - Percentages- 25% With Hemophilia • 75% Without Hemophilia • Genotype- The specific Allele makeup of an organism • - Ratios- 1 XHXH: 1 XHXh: 1XHY: 1XhY • - Percentages- 25%XHXH: 25% XHXh: 25%XHY: 25%XhY XH Y XH XHXH XHY XHXh XhY Xh Punnett square of a Normal Male and a Carrier Female
Student PracticeNow you try! Genotype: Ratio: 2 XHXh : 2 XHY Percentage: 50% Hemophilia Carrier 50% Normal Xh Y XHXh XHY XH Phenotype: Ratio: 2 XHXh : 2 XHY Percentage: 50% HY 50% hY XHXh XHY XH For example: Eye color
How to read: Circle= Female Square= Male Shaded Circle= Female Hemophilia Carrier Shaded Square= Male hemophiliac Three generation X-Linked Pedigree Chart White= Person is fine. May of two “healthy genes.” Black= Person is affected. Has 2 “bad” genes.
Student Practice:How to read an X- Linked Pedigree Chart. Jan Joe Kayla Cindy Tom Marc Dan Tom Jr. Lisa Key: Square= Male Circle= Female Red Square= Male hemophiliac Yellow Circle= Female carrier • You think you know X- linked Pedigree’s? If so: • Who is the main source of the hemophilia in this family? • How many people in this chart DO NOT have any form of hemophilia? • If Marc were to have children with a normal female, what are the odds of one of them having some form of hemophilia?