GENERAL GENETICS. AYESHA MASRUR KHAN SPRING 2013. Gene interaction. What is gene interaction? In gene interaction, genes at different loci contribute to the determination of a single phenotypic characteristic.
AYESHA MASRUR KHAN
What is gene interaction?
This plant produces peppers in one of four colors:
red, brown, yellow, or green.
The genes at the two loci then interact to produce the colors seen in F2 peppers
1. Walnut comb R_P_
2. Rose comb R_pp
3. Pea comb rrP_
4. Single comb rrpp
Similar to dominance, except that dominance entails the masking of genes at the same locus (allelic genes).
B_ E_ black
bbE_ brown (frequently called chocolate)
The presence of a beard on some goats is determined by an autosomal gene (Bb) that is dominant in males and recessive in females.
The key to understanding the expression of the bearded gene is to look at the heterozygote.
In males (for which the presence of a beard is dominant), the heterozygous genotype produces a beard but, in females (for which the presence of a beard is recessive and its absence is dominant), the heterozygous genotype produces a goat without a beard.
Genotype Male phenotype Female phenotype
HH hen feathering hen feathering
Hh hen feathering hen feathering
hh cock feathering hen feathering