Which of the Following Best Describes the Frequency of Crossing

Question

Which of the following best describes the frequency of crossing over in mammals?
A)~50 per chromosome pair
B)~2 per meiotic cell
C)at least 1-2 per chromosome pair
D)~1 per pair of sister chromatids
E)a very rare event among hundreds of cells

Accepted Answer

Studies in mammals have shown that at least 1-2 crossover events occur per chromosome pair during meiosis. The frequency may vary slightly among different species and among different regions of the same chromosome, but it is generally higher than the frequency of crossing over in other organisms such as bacteria, fungi, or insects.