Question

Two linked genes can give rise to four different gamete genotypes. Two of the gamete genotypes reflect the presence of parental type chromosomes, which have not been altered by crossing over. In contrast, the other two gamete genotypes are recombinant (non-parental). The chromosomes of these gametes carry new combinations of alleles that result from the exchange of chromosome segments during crossing over.

a) True
b) False

Answer 1

True, linked genes can produce four different gamete genotypes: two parental without crossing over and two recombinant due to crossing over, which was observed by Thomas Morgan and led to the development of linkage maps.

Step-by-step explanation:

It is true that two linked genes can give rise to four different gamete genotypes, among which two reflect the parental type chromosomes that have not been altered by crossing over, while the other two are recombinant and are a result of crossing over. This is because when genes are located close to each other on the same chromosome, they tend to be inherited together during meiosis. However, the exchange of chromosome segments during crossing over can produce new allele combinations, leading to recombinant gametes. As Thomas Morgan observed, a certain percentage of offspring in his experiments were recombinant, leading to the creation of linkage maps for genes on chromosomes.