g the inability to metabolize phenylalanine is a recessive autosomal trait called PKU when A marries a woman at random from another town what is the probability that his first born will be affected by PKU

The correct answer is - zero percent.

Explanation:

As it is known that PKU is a disease that takes place if one has wild type recessive rr only. It is given that A is normal heterozygous and if he marries normal women then

   R       r

R  RR    Rr

R   RR    Rr

so there will be 2 carriers and 2 unaffected but no affected.

each of the 46 original chromosomes splits into two daughter chromosomes, so there are two sets of 46 daughter chromosomes that end up in each cell. human cells have 46 chromosomes. each chromosome consists of a pair of identical chromatids attached together by a structure called a centromere.