Question

When population geneticists refer to a fixed allele, what do they mean?

1) that the allele is constrained by natural selection and won't be changed by mutation
2) it is the only allele remaining in a population after all of the alternatives have disappeared
3) that the genomic structure around the allele is constrained
4) all of the above

Answer 1

A fixed allele is the only allele remaining in a population after all of the alternatives have disappeared.

Step-by-step explanation:

A fixed allele refers to an allele that is the only allele remaining in a population after all of the alternatives have disappeared.