What does the term recessive refer to in genetics?

The term "recessive" in genetics specifically refers to a trait that is expressed only when an individual has two copies of the recessive allele, which is known as being homozygous for that trait. This means that if an organism inherits the recessive allele from both parents, then the characteristics associated with that allele will be observable in the organism's phenotype.

In contrast, if an individual possesses only one copy of the recessive allele along with one dominant allele (making them heterozygous), the dominant allele will mask the presence of the recessive trait, resulting in only the dominant phenotype being expressed. Therefore, a recessive trait will not be visible unless both alleles are recessive.

This key understanding of how recessive traits function is crucial in genetics, particularly in predicting offspring traits and understanding inheritance patterns. Traits that are always visible in the phenotype or expressed in heterozygous conditions would not fall under the definition of recessive traits, as these characteristics would instead be associated with dominant alleles.