Germline mutation

A germline mutation is any detectable and heritable variation in the lineage of germ cells. Mutations in these cells are transmitted to offspring, while, on the other hand, those in somatic cells are not. A germline mutation gives rise to a constitutional mutation in the offspring, that is, a mutation that is present in virtually every cell. A constitutional mutation can also occur very soon after fertilisation, or continue from a previous constitutional mutation in a parent.

This distinction is most important in animals, where germ cells are distinct from somatic cells. However, in plants, the reproductive cells in a particular flower will be derived from the same meristem as the cells in that flower and on the stem leading to the flower, which is a different population of cells than those that give rise to the other flowers on the plant. Single-celled organisms have no distinction between germline and somatic tissues.

In animals, mutations are more likely to occur in sperm than in ova, because a larger number of cell divisions are involved in the production of sperm.

Mutations that are not germline are somatic mutations, which are also called acquired mutations.