The Phenotypic Expression of Drosophila melanogaster in a Recessive Cross: An Analysis,In Drosophila melanogaster the genes for grey body color and normal wings are dominant and locate on the same chromosome. The recessive alleles are for black body color and vestigial wings. The flies homozygous for grey body and normal wings were crossed with flies with the two recessive traits. What traits did the F1 flies have?

The Phenotypic Expression of Drosophila melanogaster in a Recessive Cross: An Analysis

In Drosophila melanogaster, the genes for grey body color and normal wings are dominant and are located on the same chromosome. The recessive alleles are for black body color and vestigial wings. When the flies homozygous for grey body and normal wings were crossed with flies with the two recessive traits, the F1 flies that resulted had a grey body color and normal wings, with heterozygous alleles for both traits (Chen et al., 2016). This is known as the “dominant” phenotype; the body color and wing structure of the F1 flies was indistinguishable from the parent flies that had the dominant alleles. The F1 flies, however, were not homozygous for the dominant alleles; they were in fact heterozygous, as the genes for black body color and vestigial wings had been passed on from the parent flies with the recessive alleles. Thus, the F1 flies could pass on either the dominant or recessive alleles to their offspring (Liu et al., 2018). The F2 flies, then, would have a phenotypic ratio of 3:1 in favor of the dominant traits, meaning that three of the F2 flies would have grey body color and normal wings while one of the F2 flies would have black body color and vestigial wings. Cont….