Question

Huntington Chorea is a serious genetic disorder caused by a rare dominant allele (H) at an autosomal locus on chromosome 4. In some rural Michigan populations, the frequency of people diagnosed with the disorder is unusually high, about 0.05%.  Genetic work shows that the wild-type allele (+) mutates into H at a rate of 9.56x10^-7mutations per gamete.Use these data to estimate how many children out of 10,000,000 births to parents without the disorder will have Huntington’s Chorea. Express answer in decimal form.

Answer 1

Huntington's Chorea is an inherited disorder that affects the nervous system.

It is caused by a dominant allele. This means that it can be passed on by just one parent if they have disorder.

H+H+ - allele for the disorder

HH - allele for normal gene

If they are crossed, three normal gametes and one disordered gamete is produced.

Since, per normal gamete, 9. 56 x 10^-7 mutations are caused.

Therefore, 3 gametes would result in (3 x 9.56 x 10^-7) mutations, which is equal to

0.2868x10^-5 mutations out of 4 birth.

Therefore, out of 10,000,000 births, children with Huntington' Chorea disease are 10, 000, 000 x 0.2868 x 10^-5 /4 = 7.1700