Question

Alleles C and D together on one chromosome
Alleles c and d together on one chromosome
Alleles C and d together on one chromosome
Alleles c and D together on one chromosome
Both alleles C and d together on one chromosome and alleles c and D together on one chromosome

Answer 1

Okay, there are a few possible combinations depending on where along the chromosome arm the crossing over happens. If C and D are very close together and the crossing over event occurs either on the centromere side of both alleles or on the distal side of both alleles, they will either both be exchanged or neither will be exchanged, giving you C and D on one chromosome and c and d on the other chromosome.

If C and D are relatively far apart and the crossing over event occurs on the chromosome arm between them, then you'll get one chromosome with C d and the other one with c D.

If C and D are really, really far apart and two crossing over events occur between them (it has been known to happen, both in nature and in homework problems given to students), then you're back to the original chromosomes C D and c d.

So there are some possibilities. In the end, you really need a little more information to definitively answer this question.

Answer 2

Thanks...