Question

You breed a black, long-haired rabbit with a white, short-haired rabbit. All of the offspring have long, black hair. If the genes for hair color and length are closely linked on the same chromosome, what would you expect to see in the F₂ generation?

O 3 black, long-haired: 1 white short-haired
O 15 black, long-haired: 1 black, short-haired: 1 White, long-haired: 13 white short haired
O All long-haired black
O 9 black long haired: 3 black, short-haired: 3 white, long-haired: 1 white, short-hairedite, short-haired
O 3 black long-haired: 9 black, short-haired: 9 white, long-haired: 1 white, short-haired

Answer 1

When breeding rabbits with linked genes for hair color and length, the F2 generation is likely to display overwhelmingly the dominant parental phenotypes due to the close linkage, resulting in 'All long-haired black' rabbits if no recombination occurs.

Step-by-step explanation:

The F2 generation resulting from breeding a black, long-haired rabbit with a white, short-haired rabbit where all F1 offspring are black and long-haired would show a phenotypic ratio based on Mendelian genetics and the assumption of linked genes. However, if genes for hair color and length are indeed closely linked and there are no events like crossing over, the majority of the F2 offspring would inherit these traits together. This usually results in a less varied combination of phenotypes than what is observed with independent assortment.

Given the F1 generation all display the dominant phenotypes, and assuming no crossing over has occurred, the F2 generation should mostly mirror the dominant parental phenotypes if the genes are truly closely linked. A rare recombinant phenotype might occur, but it would be much less frequent than the non-recombinant. Thus, the expected F2 ratio, in this case, would likely be skewed in favor of the parental phenotypes, not an independent assortment ratio like 9:3:3:1.

The correct answer is 'All long-haired black' if the hair color (black) and long hair traits are both dominant and closely linked, with very minimal chance for recombination due to crossing over between these linked genes.