Sex-linked genes and pedigree charts revision (2.5)

Question 1

Define sex-linked traits

Answer 1

Sex-linked traits are traits determined by the genres found on the sex chromosomes (X and Y)

Question 2

What is a pedigree chart?

Answer 2

A pedigree chart is a chart showing how family members are related and whether or not they have a particular trait of interest.

Question 3

How can you tell whether a trait on a pedigree chart is dominant or recessive?

Answer 3

• First, you find an individual who has a different phenotype from both parents. This is only possible if both parents are carriers/ heterozygous, and the child has inherited both recessive alleles.
• If the trait is dominant, affected individuals have at least one dominant allele in their genotype. If the trait is recessive, affected individuals will be homozygous recessive.