Question

Glaucoma is a leading cause of blindness. Studies have linked a common form of glaucoma to three genes and more than 20 genetic loci. Which best describes glaucoma?
A.a recessive trait that requires multiple recessive alleles to be expressed

B.a polygenic trait that is influenced by the number of alleles present

C.a codominant trait that is expressed more often when more dominant alleles are present

D.a dominant trait that depends on the presence of only one of many dominant allele

Answer 1

i think B because

C doesnt make sense: it assumes that you can have multiple degrees of "glaucomicness"

The question says 3 genes and 20 genetic loci. what i think they mean with that is that 3 genes are dominant and it is ressesive on 20 loci so it is neither fully dominant nor fully ressesive so A and D are not correct

Answer 2

what was the answer given was it A?

Answer 3

The question is saying that three genes are known to affect the likelihood of you developing glaucoma. In addition, changes in sequence at 20 different loci (places on chromosomes) seem to be inherited more often in people who develop glaucoma, but they don't know if those loci contain genes that actually affect glaucoma. Basically, the question is telling you that at least three genes affect your likelihood of developing glaucoma. So the question to ask yourself is, which of the answers refers the inheritance pattern where multiple genes affect a single trait (presence or absence of glaucoma)?