Final answer:
Genetic interference resulted in only 10 double crossovers being observed when an investigator expected 50, due to an 80% interference rate.
Step-by-step explanation:
The student's question pertains to the concept of genetic interference, which is a factor in genetics that reduces the frequency of double crossovers in genetic recombination. If an investigator expected 50 crossovers without interference, but the interference was 80%, this means that 80% of the expected double crossovers did not occur. To calculate the number of double crossovers (DCO) observed, one can use the formula:
Observed DCO = Expected DCO x (1 - Interference)
So, plugging in the values:
Observed DCO = 50 x (1 - 0.80)
Observed DCO = 50 x 0.20
Observed DCO = 10
Therefore, the investigator would see 10 double crossovers.