What type of gene is not expressed if it is paired with a dominant gene?

The concept of dominant and recessive genes is fundamental in genetics. A recessive gene does not manifest its phenotype if a dominant gene is present in the pair of alleles. In this context, alleles are the different forms of a gene, and when two alleles are present—one dominant and one recessive—the dominant allele's trait will be expressed, overshadowing the effect of the recessive allele.

The dominant allele has the ability to mask the presence of the recessive allele, meaning that if an individual has at least one dominant allele, the recessive gene's influence will not be visible in the organism's traits or characteristics. In contrast, the dominant gene expresses its trait regardless of whether it is paired with another dominant gene or a recessive gene.

Understanding why recessive genes remain unexpressed in the presence of a dominant gene is crucial for interpreting genetic inheritance patterns, as it explains how certain traits are passed down through generations and can sometimes skip a generation when only recessive alleles are inherited without a dominant counterpart. This foundational concept in genetics allows for predictions about potential traits in offspring based on the genotypes of the parents.