There are two different alleles for the number of fingers on the hands: five-finger allele and six-finger allele. When both the five-finger allele and the six-finger allele are present in the same individual, the individual has six fingers on each hand. Which allele is dominant?

six-finger allele

Explanation:

A dominant allele is the copy of a gene located at a locus on a chromosome, whose phenotype is often expressed in the presence of the other copy of a gene in an individual. It is the allele of a gene of that override the effect of the other copy of the gene. It is dominant over the other. The other copy of the gene that it dominates is the recessive allele.

The six-finger allele that expresses itself in the same individual in the presence of the five-finger allele is the dominant allele. The five-finger allele is the recessive allele.

The six finger allele

Explanation:

In this case, the six finger allele is dominant because, the allele was the trait later observed in the individual's phenotype. A dominant allele is one of a pair of alternative forms of a gene that controls the character of which the code codes for and also mask the effect of the alternative form.

Thus, since the six finger allele was expressed masking the effect of the five fingered allele, it is thus the dominant allele.