biologyand 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.
sex cellssuch 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. For example, all cells of the mammalian liver are somatic. If there is a mutationor other genetic change in the germline, it can be passed to offspring, but a change in a somatic cell will not be.
Germline cells are immortal, in the sense that they can reproduce indefinitely. This is enabled by a special
enzymecalled telomerase. This enzyme is dedicated to lengthening the DNAprimer 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
eukaryoteof about one billion years ago, from which all plants and animals descend.
Germ line development
Wikimedia Foundation. 2010.