We have a cross between a heterzygous Aa Bb with a homozygou

We have a cross between a heterzygous A/a, B/b with a homozygous recessive a/a, b/b. What is the ratio of parental type to recombinant type of offspring assuming that the two loci are on separate chromosomes? What is the ratio assuming that the two loci are closely linked on the same chromosome (so that no recombination or crossing over between the two loci is observed)?

Solution

So, when genes are on different chromosomes, 50% of the gametes produced by a this individual would be recombinant, when compared to the gametes produced by its parents. The other 50% are parental.

If two genes occur on the same chromosome, they may or may not assort independently depends on linkage distance. Now when Linkage is present then fewer than 50% of the gametes produced by a double heterozygote are recombinant and this percentage will decrease or increase with the gene on same chromosome.