Most Genes Have Many More Than Two Alleles

Question

Most genes have many more than two alleles.However,which of the following is also true?
A)At least one allele for a gene always produces a dominant phenotype.
B)Most of the alleles will never be found in a live-born organism.
C)All of the alleles but one will produce harmful effects if homozygous.
D)There may still be only two phenotypes for the trait.
E)More than two alleles in a genotype is considered lethal.

Accepted Answer

Although most genes have many alleles, only two of them are expressed in a diploid organism at a given time, resulting in two possible phenotypes for the trait. The presence of multiple alleles for a gene provides genetic variation within a population. It is not necessary for at least one allele to produce a dominant phenotype, as some traits may be controlled by recessive alleles. It is also not true that most alleles will never be found in a live-born organism, and it is not the case that all but one allele will produce harmful effects if homozygous. Lethality is not always associated with having more than two alleles.