Answer:
Option B
Explanation:
Complete question is
The original mother resulted from a cross between two flies from true breeding lines.
What are the genotypes of these two lines? (Note that the chromosomes are NOT
indicated this time).
a) pr+ pr+ cn cn and pr pr cn+ cn+
b) pr+ pr+ cn+ cn+ and pr pr cn cn
c) pr+ pr+ cn cn and pr pr cn cn
d) pr pr cn+ cn+ and pr+ pr+ cn cn
e) either a) or d) could be true.
Solution
True breeding species will have the same allele pairs for their characteristic traits.
It is given that mother of the progeny has arisen from two true breeding lines
Thus, both the parents must have same allele in the allele pair of their genotype
Also the female has wild type eyes, thus her genotype would be pr+cn/pr
Therefore the genotype of parents is
pr+ pr+ cn+ cn+ and pr pr cn cn
There by producing all offspring with genotype pr pr + / cn cn+
Hence, option B is correct
