Question 1
Gene interactions in which an allele of one gene modifies or prevents expression of alleles of another gene is known as ________.
◦ pleiotropy
◦ incomplete dominance
◦ codominance
◦ epistasis
◦ incomplete penetrance
Question 2
In certain goat breeds, appearance of a chin beard is a sex-influenced trait. Recall that bearding is inherited as an autosomal trait determined by two alleles,
B1 and
B2, and females must be homozygous for the bearded allele,
B2, to have a beard. What genotypes must a bearded billy goat (male) and a beardless female goat have if they have a bearded female offspring?
◦ The bearded billy goat must be heterozygous for the bearded allele, while the beardless female must be homozygous for the bearded allele.
◦ Both the bearded billy goat and beardless female must be heterozygous for the bearded allele.
◦ The bearded billy goat could be heterozygous or homozygous for the bearded allele, while the beardless female must be heterozygous for the bearded allele.
◦ Both the bearded billy goat and beardless female must be homozygous for the bearded allele.
◦ The bearded billy goat could be heterozygous or homozygous for the bearded allele, while the beardless female must be homozygous for the bearded allele.
Eye Color Is a Sex-Linked Trait in Drosophila
New England children like David, Joanna, and Abigail Mason (painted by an unknown artist around 1670
Teen eating habits are often influenced by peers and social settings
A graphic depiction of predisposing alleles characteristic of a threshold trait within a population,
goat anatomy
A polygenic model for a threshold trait