The role of heritable variation
Heritable variation provides material for biological evolution. The heritable variation is mainly gene mutation, gene recombination and chromosomal variation. Gene mutation refers to the change of gene structure, including the addition, deletion or change of DNA base pairs. Gene recombination refers to the recombination of genes that control different traits. They can all occur during the formation of germ cells and can be passed on to offspring, causing mutations in offspring.