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The Phenotypic Expression of Drosophila melanogaster in a Recessive Cross: An Evaluation
In Drosophila melanogaster, the genes for gray physique coloration and regular wings are dominant and are situated on the identical chromosome. The recessive alleles are for black physique coloration and vestigial wings. When the flies homozygous for gray physique and regular wings have been crossed with flies with the 2 recessive traits, the F1 flies that resulted had a gray physique coloration and regular wings, with heterozygous alleles for each traits (Chen et al., 2016). This is called the “dominant” phenotype; the physique coloration and wing construction of the F1 flies was indistinguishable from the mum or dad flies that had the dominant alleles. The F1 flies, nonetheless, weren’t homozygous for the dominant alleles; they have been the truth is heterozygous, because the genes for black physique coloration and vestigial wings had been handed on from the mum or dad flies with the recessive alleles. Thus, the F1 flies may move on both the dominant or recessive alleles to their offspring (Liu et al., 2018). The F2 flies, then, would have a phenotypic ratio of three:1 in favor of the dominant traits, which means that three of the F2 flies would have gray physique coloration and regular wings whereas one of many F2 flies would have black physique coloration and vestigial wings.
