The process by which such a sudden structural change occurs, either through an alteration in the nucleotide sequence of the DNA coding for a gene or through a change in the physical arrangement of a chromosome.

• 突变，变种突变发生的过程，是通过基因的脱氧核糖核酸密码的核苷酸顺序的改变或者通过染色体内部的物理重新排列