Suppose a geneticist uses a three-point testcross to map three recessive, linked hummingbird wing- snape mutations called tk. f. and b. where tk is associated with thick wings; f is associate with fiat wings; and b is associated with blunt wings. He ?rst crosses homozygous blunt birds to homozygous thick, fiat birds. Next, he backcrosses the F1 progeny to thick, ?at, blunt birds. He obtained the following results.
Given this data, label the progeny phenotypic classes as either parental, single crossover (800). Or double crossover (DCO) recombinant types. Each label may be used multiple times. Two classes have already been filled in for you.
