What is the difference between dominant and recessive traits?

Dominant and recessive traits describe how different alleles express themselves in an organism’s phenotype.

A dominant trait is expressed even if only one copy of the allele is present, while a recessive trait is expressed only when both alleles are the same and recessive.

Key differences:

• Expression:
  Dominant trait is expressed in both homozygous (TT) and heterozygous (Tt) conditions;
  Recessive trait is expressed only in homozygous condition (tt).

• Allele representation:
  Dominant alleles are represented by capital letters (T);
  Recessive alleles are represented by small letters (t).

• Masking effect:
  Dominant allele masks the expression of the recessive allele in heterozygous condition.

• Frequency of expression:
  Dominant traits appear more frequently in offspring when present; recessive traits may skip generations.

• Examples:

  • Tallness (T) is dominant over dwarfness (t) in pea plants

  • Brown eye color is dominant over blue in humans

In simple terms: A dominant trait shows up even with one allele, while a recessive trait appears only when both alleles are recessive.