Variation in gene expression

Question 1

Variable gene expressivity

Answer 1

same genotype in different individuals can have variable
influence on strength of phenotype. individuals w. same allele for a gene involved in
quantitative traits like body height might have large variance

Question 2

Variable gene penetrance

Answer 2

• % of individuals w. given genotype has an expected
  phenotype. (Hence some individuals that carry mutant gene are ill + others are symptom
  less)

Question 3

Sex is determined by factors at birth

Answer 3

1) presence/absence of Y chromosome,
2) type of gonads (sex glands), 3) sex hormones, 4) int. reproductive anatomy (such as uterus in
females) , + 5) ext. genitalia