In a species of salamander, a cross between white eyed males and pink eyed femal
ID: 169291 • Letter: I
Question
In a species of salamander, a cross between white eyed males and pink eyed females produced an F1 generation where all had wild type red eyes. Crosses of the F1 yielded the following data: Red eyes 1357 White eyes 753 Pink eyes 438 What is the mode of inheritance and how many genes are segregating? What was the genotype of the P generation of this cross? Draw the gentoypes of the F1 generation red eyes X red eyes cross from above and the phenotypic ratios of the progeny. Match the progeny phenotypes with the correct possible progeny genotypes. In a second cross of a white x a pink, 4/16 were red, 4/16 were pink, and 8/16 were white What were the genotypes of the parents of this cross?Explanation / Answer
This is a typical example of incomplete dominance. Both the salamanders are expressing their genotype. Below is an example of cross between parents
RR
White eyed male
rr
Pink eyed female
Rr
Red eyed male
Rr
Red eyed female
Further, when the cross was done between F1 generation, three different types of characters were obtained as shown below
Rr
Red eyed
Rr
Red eyed
RR
White eyed
rr
Pink eyed
Rr
Red eyed
Rr
Red eyed
So, in a cross between the two F1 generations, a homozygous red eyed and a homozygous white eyed salamander is formed. In addition, two red eyed heterozygotes were also formed. One gene is segregating in this cross.
The P generation of this cross were homozygous in nature since the combination of both had a blended effect. So in this example, white eyed salamander had RR genotype and pink eyed salamander had rr genotype.
RR
White eyed male
rr
Pink eyed female
Rr
Red eyed male
Rr
Red eyed female