Topic 8: Gene Interaction

Question 1

complete dominance

Answer 1

phenotype is determined by the dominant, haplosufficient allele

Question 2

incomplete dominance

Answer 2

phenotype of heterozygote is an intermediate of that of either allele

Question 3

co-dominance

Answer 3

phenotype of heterozygote displays both alleles equally

Question 4

pleiotropic

Answer 4

affects more than 1 character (syndromes w more than one condition)

Question 5

genetic load

Answer 5

all deleterious and lethal alleles present in individual members of a population

Question 6

epistasis

Answer 6

allele of one gene masks expression of the alleles of another gene and expresses its own phenotype instead (9:3:4 or 12:3:1)

Question 7

suppressors

Answer 7

an allele of one gene reverses the effects of mutation of another gene (13:3)

Question 8

synthetic lethals

Answer 8

2 viable single mutants may cause lethality when crosses to generate a double mutant (9:3:3)

Question 9

duplicate genes

Answer 9

2 or more functional copies of certain genes (teleosts), alleles of either copy can affect the genetic ratio (15:1)

Question 10

penetrance

Answer 10

% of individuals with a given genotype who exhibit the associated phenotype

Question 11

expressivity

Answer 11

the extent to which a given genotype is expressed at the phenotypic level