AP BIOLOGY

Detailed explanation-1: -If the trait is dominant, one of the parents must have the trait. Dominant traits will not skip a generation. If the trait is recessive, neither parent is required to have the trait since they can be heterozygous.

Detailed explanation-2: -One trick for identifying a recessive trait is that if a trait skips a generation in a pedigree, it is often an autosomal recessive trait (although a trait can be autosomal recessive and not skip generations). These traits appear with equal frequency in both sexes.

Detailed explanation-3: -Recessive traits like red hair can skip generations because they can hide out in a carrier behind a dominant trait. The recessive trait needs another carrier and a bit of luck to be seen. This means that it can sometimes take a few generations to finally make its presence known.

Detailed explanation-4: -Recessive alleles only show their effect if the individual has two copies of the allele (also known as being homozygous?). For example, the allele for blue eyes is recessive, therefore to have blue eyes you need to have two copies of the ‘blue eye’ allele.