Chapter 14, Problem 12TYPSS

Summary Introduction

To review:

Based on the observation in a study, predict the genotypes of the green plants and color encoded by each of these genotypes. Further, determine the fraction of the total progeny exhibiting each type of color.

Introduction:

A gene could be autosomal or sex-lined in nature. An autosomal gene is the one that is present on the numbered chromosome other than sex chromosomes. Sex-linked genes are those that are present on X and Y chromosome.

The two autosomal genes that are located on different chromosomes control the production of feather pigment in parakeets. Gene B codes for an enzyme that is required for the synthesis of a blue pigment, and gene Y codes for an enzyme required for the synthesis of a yellow pigment. Green results from a mixture of yellow and blue pigments, and recessive mutations that prevent production of either pigment are known for both genes. Suppose that a breeder has two green parakeets and mates them. The offspring are green, blue, yellow, and albino (unpigmented).