The situation in which one member of a pair of allelic genes express itself over the other member is called dominance. The allele which fails to express is termed recessive allele. In Tt(tall), ‘T’ is the dominant allele and ‘t’ is recessive, as dwarfness is not expressed. Recessive alleles are expressed only in homozygous individuals. Homozygous genotype ‘tt’ is dwarf.
Dominance vs Recessive
|Dominance allele it is able to express itself even in the presence of its recessive allele.||Recessive allele or factor is unable to express its effect in the presence of dominant allele.|
|It does not require another similar allele to produce its effect on the phenotype. eg: Tt is tall||It produces allele its phenotypic effect only in the presence of similar allele, e.g., tt is dwarf.|
|Dominant allele or factor can form complete polypeptide or enzyme for expressing its effects e’g’, red colour of flower in pea.||The recessive allele forms an incomplete or defective polypeptide or enzyme so that the expression consists of absence of the effect of dominant allele, e,g., white flower colour in pea.|