Assume that a cross is made between AaBb and aabb plants and that the offspring occur in the following numbers: 106 AaBb,48 Aabb,52 aaBb,94 aabb.These results are consistent with ________.
A)sex-linked inheritance with 30% crossing over
B)linkage with 50% crossing over
C)linkage with approximately 33 map units between the two gene loci
D)independent assortment
E)100% recombination

Question

Quizplus · Accepted Answer

The results suggest linkage between the two gene loci, and the frequency of recombination between them can be estimated as the percentage of offspring that show a recombinant phenotype (Aabb and aaBb, which have different combinations of alleles than the parental types). The total number of recombinant offspring is 48 + 52 = 100, out of 300 total offspring. This gives a recombination frequency of 100/300 = 0.33 or 33%. This corresponds to a map distance of approximately 33 map units (centimorgans) between the two loci, assuming that crossing over occurs randomly and independently between them. The other choices do not fit the observed results or are not relevant to this type of cross.

Assume That a Cross Is Made Between AaBb and Aabb