If a child inherits two recessive genes, say one for blue eyes and one for green eyes, which trait will show?
In: 21
Genes per se are not dominant or recessive, alleles are. A given gene may come in many slightly different variations, and those are called alleles.
There’s nearly always one allele that’s more dominant than the other, because being a dominant/recessive allele is not an absolute status, it’s relative to what the other allele is. The same allele can behave as either recessive or dominant depending on what other allele it’s paired with.
There are cases in which neither of the two alleles really dominates over the other, that is known as codominace and results in both of them being expressed in the phenotype, for example the AB blood group is the result of the codominace between the allele A and the allele B of a gene called ABO.
Your specific example is flawed, since human eye color is not a mendelian trait despite what most people believe, meaning it doesn’t depend on just one gene.
Latest Answers