Question

The figure below illustrates a hypothetical metabolic pathway for feather color in parrots. Purple feathers result from the combination of red pigment deposited by the protein product of the I allele and blue pigment deposited by the protein product of the R allele. No pigment/ivory → Red pigment Purple pigment

If you test cross a purple bird that is heterozygous at one, but not both loci, what are the possible phenotypic outcomes for the offspring?

for each outcome give the genotype of the cross (both purple and the testcross parent phenotypes- and the phenotypic ratio expected in the offspring from that cross.

iirr is Ivory/no pigment

I_R_ & iiR_ are both purple

I_rr is red.

Answer 1

Civory , Ans: alo pigments 1. , Red Pigments R-, Purple Pigment hirr lire 1-R-or iR- Let Tast cross between i Purple bird that is Heterozygous at one loci ine its genotype will be iiR since Tect cross- involver cross between An Individual with a phenotypically Recessive Individual ie ivory / No pigmentation. T Therefore, Here in giren example then * Crogs will take place between * i i Rr Leone X ürr - ir iR liko ir i Rr ir iin ir ring Genotypec Ratio - 8 CiiRo ) : 8 (ion) ie 1:1 Phenotypic atio ! 8 (Purple) : 8 (Ivory) ole 1:1 Phenotypes of test cross parents 7 Rr x ling