Name L311 Genetics Problem Set 5 week of February 27 Due in

Name L311 Genetics Problem Set #5 week of February 27 Due in your discussion group the You are encouraged to work in groups on these problems, but you should write your own answers do not copy directly from classmates or any other source. Please show your work and define your symbols clearly. 1. Duchenne muscular dystrophy is an X-linked recessive disorder that causes progressive muscle weakening a) consider a healthy woman whose brother has Duchenne muscular dystrophy. What is the probability she will have an affected child? (2 pts) b) If your mother\'s brother (your uncle) has Duchenne muscular dystrophy, what is the probability that you have inherited the disease allele? (2 pts)

Solution

(1)

Answer: 1/8

Affected brother: XmY

Woman whose brother is affected: XX or XmX (1/2 or 50% chances that she is a carrier)

If a carrier female marries a normal man there is ¼ chances that she could have a child with Duchenne dystrophy.

The above mentioned woman is ½ being a carrier, therefore probability of having a child with Duchenne dystrophy is ½ x ¼ =

(b)

If a carrier female marries a normal man there is ½ child will inherit the disease allele.

My mother being a disease carrier = ½

Me carrying the disease allele= ½ x ½ =1/4