Cloning and genomic sequencing projects have identified many repetitive sequences in the human genome. Some of these are simple nucleotide repeats that vary in number between individuals but are inherited.

如果将一个家族成员酶解后的基因组用能够检测这些重复序列的探针进行southern杂交，每个样本都会显现长度不同的一系列条带（在两个侧翼区制性酶切位点之间的重负序列的长度不同，侧翼区是个术语）。一些条带和母亲的一致，同时一些是与父亲的一致。