When two or more forms of the gene for a single trait exist some forms of the gene my be?

When two or more forms of a gene for a single trait exist, these different forms are called alleles. Some alleles may be dominant, which means they will express their traits even when only one copy is present, while others may be recessive, requiring two copies for their traits to be expressed. This variation in alleles contributes to the genetic diversity observed in populations. Additionally, some alleles may be co-dominant or exhibit incomplete dominance, leading to a range of phenotypic expressions.