Melanism is defined broadly as an increase in dark pigment in the feathers, giving them a blackish appearance. Melanism is also associated with mutations in the gene encoding the melanocortin 1 receptor (MC1R), a protein important in modulating melanin pigmentation. As a result, the allele frequency of the dominant mutation increased in the gene pool, and the majority of moths in nature seemed to be melanistic. By 1895, 98% of moths in Manchester and Birmingham were melanocytic. Individuals with characteristics that improve their survival and procreation in a certain environment are favored by natural selection, which can influence the frequency of melanistic genes in a population.