Question

Since each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent,

Answer 1

Answer:

d. no matter what the first child's phenotype, the next child will have a 1/4 chance of being phenotypically recessive.

Explanation:

The birth of any child with a particular trait is an independent event which means that it does not matter what is the phenotype/genotype of first child, it will not impact the phenotype/genotype of the next child.

In general, each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent. Then in such scenario, the probability of a child to be born with a recessive phenotype is 1/4.

Let us consider a trait with alleles R and r. The cross is depicted in the picture attached. It is clear from the picture that out of the 4 probable progeny, 3 with 'genotype RR, Rr and Rr' will show dominant trait phenotypically while only 1 with 'genotype rr' will show recessive trait. It means that chance of dominant progeny is 3/4 while that of recessive progeny is 1/4.

But, birth of the child is independent event so if first child is born with recessive trait, the next child will still have 1/4 chance of having recessive trait phenotypically .