What makes a gene dominant or recessive?

Answer 1

The most basic explanation is that a dominant gene needs only one allel present to control the phenotype where as a recessive gene needs to have both present. Often a gene is dominant because it produces the protein needed to produce the phenotype where as the recessive gene produces a protein for a different phenotype (which can be overpowered) or simply doesn't produce a protein at all.

Answer 2

A dominant gene will be expressed if one allele (out of 2 possible) is present, while a recessive gene requires both copies to be the recessive allele.

Answer 3

These answers are partially correct. Dominant vs recessive describes genetic mutations. For example, a mutation may be recessive, indicating both copies of the gene need to have the mutation in order to express the phenotype. Or one copy of the mutation may be all that is required, in this case it's a dominant mutation. Also this only works in diploid organisms (ie humans). The concept of a gene being dominant or recessive is simply incorrect.

Answer 4

Every allele produces its own unique enzyme. If the enzyme has a noticeable effect on offspring, the gene is DOMINANT.
If the enzyme has a minor or no effect on the offspring, the gene is RECESSIVE.

Hope this helps! :) :) :)