Chapter 2 Terms

Question 1

the alleles of one gene mask the effects of alleles of another gene

Answer 1

epistasis

Question 2

genes whose alleles alter phenotypes produced by the action of other genes

Answer 2

modifier genes

Question 3

a genotype is lethal in some situations but visible in others

Answer 3

conditional lethal

Question 4

environmental condition that allows conditional lethals to live

Answer 4

permissive condition

Question 5

less than 100% of the individuals possessing a particular genotype express it in their phenotype

Answer 5

reduced penetrance

Question 6

a trait produced by the introduction of alleles of multiple genes and often also the environment

Answer 6

complex trait

Question 7

the heterozygote resembles neither homozygote

Answer 7

incomplete dominance

Question 8

both parental phenotypes are expressed in the F1 hybrid

Answer 8

codominance

Question 9

a heritable change in a gene

Answer 9

mutation

Question 10

one gene affects more than one trait

Answer 10

pleiotropy

Question 11

individuals with the same genotype have related phenotyoes that vary in intensity

Answer 11

variable expressivity