In the experiment in Figure 6.6, Stern studied the inheritance pattern of crosses in which female fruit flies carried two abnormal X chromosomes, in order to find a relationship between genetic recombination and the physical exchange of chromosome pieces. Is it necessary to use a strain carrying two abnormal chromosomes, or could he have used a strain in which females carried one normal X chromosome and one abnormal X chromosome with a deletion at one end and an extra piece of the Y chromosome at the other end?

Figure 6.6

Transcribed Image Text:

Female gametes B car Crossing over B* car B car B+ car (a) X chromosomes found in Stern's flies and the result of them crossing over Male gametes * B*car Y Phenotype X chromosome from female Bcar Bcar Bcar Bar, carnation B car B'car Y eyes B*car B-car B'car B-car Y Round, red eyes B+ car+ B*car B'car Round, B+ car B-car carnation B'car Y eyes Bcart Bcar Bcar Bar, red B car Bicar eyes (b) The results of Stern's crosses