DNA, RNA, Chromosomes, and Genes


Can one gene control another?

No, one gene cannot actually control another gene, but one gene can mask the effect of another gene, which is a process called epistasis. For example, a gene in Labrador dogs controls the amount of melanin—in particular the dominant allele B results in large amounts of melanin; a recessive allele b causes less amounts. When bred, a BB or Bb dog is black, while a bb dog is brown. Yet another gene controls whether or not melanin is there at all—the gene E allows for more amounts of melanin while the recessive form e does not. When bred, an ee dog is yellow, while an Ee or EE dog is not yellow and has melanin. Thus, interaction of two genes, the B and E genes, controls coloration in Labrador dogs.

Some birth defects, such as clubfoot, are the result of polygenic inheritance in which both the mother and father must donate a gene that results in the malformation.


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