Module 2.3 Flashcards
Genes that do not mask the effects of another gene but modify the expression of another gene
For example gene D color intensity affecting color of gene B coat color
Modifier gene
Same phenotype but different genotype
Phenocopy
Genes determine the same pphenotype but produce new phenotypes through their genetic interaction
Example is chicken comb affected by both genes
9:3:3:1
Non-epistatic Inter-allelic genetic interaction
Chicken comb
R-P-
rrP-
R-pp
rrpp
Walnut
Pea
Rose
Single
One gene masks or modifies the effect of another gene pair and alters the phenotype
Example is when dogs have Gene E which controls melanin production and Gene B which controls if melanin is deposited in fur at all
Same with mice coat patterns
Epistasis
Caused by the dominant allele of one gene masking the action of either allele of one gene AT ANOTHER LOCUS
Notably A-B- and A- bb- would cause pink
A- is the important gene
Dominant epistasis 12:3:1
One gene when dominant is epistatic, and when the other gene is homozygous recessive it is epistatic to the first
NOTABLY, A- bb causing YELLOW in otherwise green color
bb is the important gene
Dominant suppression
13:3
BOTH DOMINANT ALLELE NEEDED to form the special phenotype
A- B-
Complementary gene action
Sweet pea
Lathyrus odoratus
ANY OF THE DOMINANT ALLELES causes the special phenotype
A-
OR
B- can cause it
Duplicate Dominant Epistasis
Both genes are involved in the expression of the shape
A- and B- cause one phenotype
A- bb or aa B- share a phenotype
aa bb another phenotype
Dominant Gene Interaction
Homozygous recessive genotype masks expression at another locus even with dominant genotype on that other locus
bb even with A- would still make it YELLOW rather than purple
bb is important
Recessive epistasis
VARYING DEGREES OF DOMINANCE but ALL DIFFERENT PHENOTYPES
Duplicate genes with additive effect
