Germline
From Wikipedia, the free encyclopedia
In biology and genetics, the germline of a mature or developing individual is the line (sequence) of germ cells that have genetic material that may be passed to a child.
For example, sex cells, such as the sperm or the egg, are part of the germline. So are the cells that produce sex cells, called gametocytes, the cells that produce those, called gametogonia, and all the way back to the zygote, the cell from which the individual developed.
Cells that are not in the germline are called somatic cells. Such are, for example, all cells of the liver. If there is a mutation or other genetic change in the germline, it will be/can be passed to offspring, but for a change in a somatic cell it will not be.
Germline cells also have the distinction of being immortal, i.e., they are supported by a special enzyme called telomerase. This enzyme is dedicated to lengthening the DNA primer of the chromosome, allowing for unending duplication. Somatic cells, by comparison, can only divide around 30-50 times, as they do not contain telomerases.
"Germline" can refer to a lineage of cells spanning many generations of individuals; for example, the germline that links any living individual to the hypothetical first eukaryote of about one billion years ago, from which all plants and animals descend.
