A polygenic trait is controlled by 3 genes A, B and C. In a cross AaBbCc$ imes AaBbCc$, the phenotypic ratio of the offsprings was observed as 1 : 6 : x : 20 : x : 6 : 1. What is the possible value of x?

Question

A polygenic trait is controlled by 3 genes A, B and C. In a cross AaBbCc$	imes AaBbCc$, the phenotypic ratio of the offsprings was observed as 1 : 6 : x : 20 : x : 6 : 1. What is the possible value of x?

Dr. Abubacker · Accepted Answer

Polygenes show polygenic inheritance or quantitative inheritance. As genes are present on different chromosomes they will segregate independently during meiosis. Number of individuals in F2 = 4 ௡ ݊ = number of genes present = 4 3 = 64 individuals 1+6+2x+20+6+1=64 2x=64-34 = ݔ 30 2 = 15

Q. A polygenic trait is controlled by 3 genes A, B and C. In a cross AaBbCc$\times AaBbCc$, the phenotypic ratio of the offsprings was observed as 1 : 6 : x : 20 : x : 6 : 1. What is the possible value of x?

Explanation

Reviewed by Dr. Abubacker

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