dominant allele biology definition
Dominant allele is the allele that determines phenotypical features that manifest in homozygous or heterozygous genotype s. In Genetics the dominant allele is represented in uppercase, e.g., 'A', and its recessive allele is written in lowercase, 'a'.ecessive allele: an allele that only has an effect on the phenotype when present in the homozygous state. dominant allele. In a heterozygote, the allele that is fully express ed in the phenotype.