Genetic transmission

Question 1

A couple are both carriers for an autosomal recessive disorder. They have four children. What is the probability that at least one child is affected?

Answer 1

It is easier to determine how many are not effected. That would be (3/4)⁴. This is 81/256. The difference (175/256) is the probability that at least one child will be affected

Question 2

centimorgan

Answer 2

the genetics length over which, on average, one crossover occurs in 1% of meiosis

Question 3

There are two alleles at the marker site: A and B, and
the distance between the marker locus and the disease locus is estimated to be 5 cM.

Answer 3

2(centimorgan) – 2(centimorgan)² = 0.0950.

2(0.05)-2(0.05)²

0.1-0.005= 0.0950

Question 4

A recessive condition has a population frequency of 1:90,000. Choose the number below that is
closest to the number of generations required to reduce the allele frequency by half, assuming that
all homozygous individuals are unable to reproduce?

Answer 4

n = 1/q = 300