Discussion:
Dihybrid cross analysis
A locus in mice has been identified as determining pigment production.When parents heterozygous at this locus are mated, 3/4 of the progeny are coloured and 1/4 are albino.Another locus determines the actual coat colour; for example, when two yellow mice are mated,2/3 of the progeny are yellow and 1/3 are agouti.It was noticed that the albino mice cannot express whatever alleles they may have at the independently assorting locus.
a. When yellow mice are crossed with albinos, they produce F1 mice in the approximate proportions of 1/2 albino,1/3 yellow and 1/6 agouti.What are the probable genotypes of the parents?
b. If yellow F1 mice are crossed among themselves, what phenotypic ratio would you expect among the progeny?
c. What proportion of the yellow progeny produced here would be expected to breed true?