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Introductory Animal Genetics
Animal Science 221

Linkage and Crossing-Over:
Calculating Recombination Frequency

In rabbits the dominant allele B produces a black coat color and the recessive genotype bb produces a brown coat.

Body fat color in rabbits is white if a dominant allele Y is present and yellow if the genotype is yy.

Assume the mating between rabbits with the following genotypes :
Black with white fat - BBYY
Brown with yellow fat - bbyy

produces the dihybrid - BbYy

Calculate the recombination frequency if the dihybrids are mated back to brown rabbits having yellow fat, bbyy, and the following ratio of phenotypes is observed:

Phenotype
Coat colorFat color# Observed
BlackWhite125
BlackYellow75
BrownWhite85
BrownYellow115

Recombination frequency:


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