Question

If a dominant gene is lethal (fitness = 0), why do you continue to see it in a population?

(A) some individuals are carriers
(B) it is "protected" in homozygotes
(C) it is "protected" in heterozygotes
(D) it continues to arise as a new mutation

Answer 1

A dominant gene can continue to exist in a population due to carriers, protection in homozygotes, and new mutations.

Step-by-step explanation:

When a dominant gene is lethal, it can still exist in a population for a few reasons:

1. Some individuals can be carriers of the gene, meaning they have one copy of the lethal allele but do not exhibit the lethal phenotype.
2. In some cases, the lethal phenotype is protected in homozygotes, meaning individuals with two copies of the lethal allele die before reproducing, preventing the gene from being transmitted further.
3. The gene can continue to arise as a new mutation, although dominant lethal alleles are relatively rare.