Which genotype represents a recessive trait?

The genotype that represents a recessive trait is homozygous recessive (e.g., aa). In genetics, traits are often influenced by alleles, which can be dominant or recessive. A recessive trait will only be expressed in the phenotype when an individual has two copies of the recessive allele (one from each parent), which is the condition represented by homozygous recessive.

In the case of homozygous recessive (aa), both alleles are recessive, meaning the characteristic associated with that recessive allele will be expressed. For example, if "a" represents a recessive trait such as blue eye color, only individuals with the genotype "aa" will exhibit this trait.

In contrast, heterozygous dominant (Aa) and homozygous dominant (AA) genotypes include at least one dominant allele, which masks the expression of the recessive trait. Heterozygous recessive, as described here (aA), is a confusing term, as heterozygous typically confers dominance to the dominant allele in a pair. Therefore, homozygous recessive is the definitive representation of a recessive trait in the context of genetics.