ABSTRACT
Evolution in biological systems is a process that brings about genetic changes in a population that are heritable and are passed on to many generations. Such changes result in an increase in divergence between vertebrates with time. For evolution to occur, alleles have to undergo change in response to agents of evolution. Alleles are different variations of the same gene that occupy the same locus on homologous chromosomes. Alleles differ in their DNA sequence and are usually recognized by their phenotypic effects. A single allele from each locus is inherited separately from each parent and alleles code for contrasting forms of a particular trait, for example color.
