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Sex Determination & How to solve sex-linked genetics problems. In Humans:. X X =. X Y =. The X chromosome is a very large chromosome with many active genes. .
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Sex Determination &How to solve sex-linked genetics problems
In Humans: X X = X Y = The X chromosome is a very large chromosome with many active genes. The Y chromosome, however, is very small & has one small active region that is called “the Sex determining Region of the Y chromosome” a.k.a. the SRY.
Sex-Linked Genetics For instance, the gene for normal blood clotting is sex-linked. There are two alleles: When we talk about traits (genes) that are “sex-linked” that’s genetics code for that gene is located on the X chromosome (and not on the Y). H = normal blood clotting h = hemophilia (a blood clotting disorder)
Hemophilia is sex-linked • Since it is sex-linked we have to write the alleles on the X chromosome. So the correct way to write this is on the X’s is as a superscript: XH = normal blood clotting Xh= hemophilia
How to Solve Sex-linked Genetics Problems The Problem: If a normal woman, whose father was a hemophiliac, marries a hemophiliac man, what are the odds any of their children will have hemophia? 1. Write the letters: XH = normal blood clotting Xh= hemophilia XHXh x XhY 2. Write the cross: 3. Punnett Square: 4. Solve the problem: Each child will have a 50% chance of having hemophilia