Modifying Genes

What are Modifying Genes or Modifier? – Definition

Modifier or modifying gene is the gene which affects or alters the expression of some other non-allelic gene.

Examples of Modifying Genes or Modifier

  • White spotting on coat of pig
  • Coat color in mice

In mice, B gene is dominant (Visit – Dominance) for coat color and codes for black coat. Recessive b gene codes for a brown coat. The intensity of coat color is affected by another gene, gene D. The D gene affects expression of both, B and b genes. The D gene in dominant form, codes for full color and in recessive form it fades the expression of the coat color genes. The D gene acts as modifier here.