Question

A hypothetical organism (2n), has either blue or orange wings as the consequence of one of its genes on chromosome 12, and has either long or short antennae as the result of a second gene on chromosome 19, as shown in the figure below.  


A certain female's number 12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene. As cells in her ovaries undergo meiosis, which of the following combinations of genes and chromosomes will her eggs have?

		One chromosome 12 with one orange gene and one chromosome 19 with one short gene
		One blue or one orange gene plus one long or one short gene (all combos possible)
		One chromosome 12 with one blue gene and one chromosome 19 with one long gene
		Two number 12 chromosomes both with blue genes OR both with with orange genes
		Two number 19 chromosomes both with long genes OR both with short genes

Answer 1

the two genes on the two chromosomes assort independently and during meiosis when in the ovaries there is only one set of chromosome found, then one chromosome 12 and one chromosome 19 will be present.

In the diploid condition(2n), both the alleles are for the blue gene on chromosome12, and thus when any one allele becomes a part of the ovarian chromosomal arrangement, it is also blue from chromosome12.

Also, in the diploid condition, both the alleles are for the long gene on chromosome 19, so when one allele becomes a part of the ovary, it is also long one from chromosome19.

So, during meiosis in the ovary, one blue counterpart of chrosome12 and one long counterpart of chromosome 19 is present.

One chromosome 12 with one blue gene and one chromosome 19 with one long gene(option 3) in the eggs is found.