Overview of interacting Genes Video Lessons

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# Problem: In a cross between a strain of large guinea pigs and a strain of small guinea pigs, the F1 are phenotypically uniform, with an average size about intermediate between that of the two parental strains. Among 1017 F2 individuals, 1 is about the same size as the small parental strain and 1 is about the same size as the large parental strain.How many gene pairs are involved in the inheritance of size in these strains of guinea pigs? A) five B) two C) four D) three

###### FREE Expert Solution

To calculate for the number of genes controlling a phenotype:

$\mathrm{r}=\frac{1}{{4}^{\mathrm{n}}}$

where r = proportion of offspring exhibiting extreme phenotypes in F2

n = number of genes controlling the trait

###### Problem Details

In a cross between a strain of large guinea pigs and a strain of small guinea pigs, the F1 are phenotypically uniform, with an average size about intermediate between that of the two parental strains. Among 1017 F2 individuals, 1 is about the same size as the small parental strain and 1 is about the same size as the large parental strain.

How many gene pairs are involved in the inheritance of size in these strains of guinea pigs?

A) five

B) two

C) four

D) three