77 3.1 Historical development of the chromosome theory Hence, this pair of reciprocal crosses does not give simi-lar results, and the wing phenotypes in the second cross are associated with the sex of the moths. Note that the female progeny of this second cross are phenotypi-cally similar to their fathers, as the males are to their mothers. Later William Bateson found that in chickens the inheritance pattern of a feather phenotype called barred was exactly the same as that of dark wing color in Abraxas . The explanation for such results came from the lab-oratory of Thomas Hunt Morgan, who in 1909 be-gan studying inheritance in a fruit ﬂy (Drosophila melanogaster). The choice of Drosophila as a research or-ganism was a very fortunate one for geneticists—and es-pecially for Morgan, whose work earned him a Nobel prize in 1934. The normal eye color of Drosophila is dull red. Early in his studies, Morgan discovered a male with com-pletely white eyes. He found that reciprocal crosses gave
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