What is a key characteristic of a dominant allele?

A dominant allele is characterized by its ability to mask the expression of a recessive allele in a heterozygous individual. This means that if an organism has one dominant allele and one recessive allele for a particular gene, the dominant allele will be phenotypically expressed, while the recessive allele will not contribute to the phenotype. This masking effect is important in understanding inheritance patterns and predicting phenotypic outcomes in offspring.

In many genetic traits, the presence of just one copy of a dominant allele is sufficient for the dominant characteristic to manifest, regardless of whether there is a recessive allele present. This quality is foundational in Mendelian genetics and has practical implications in fields like nursing, where understanding genetic conditions is crucial for patient care and education. The ability of a dominant allele to overpower the expression of its recessive counterpart is a key aspect of genetic inheritance and is fundamental to the study of genetics.