Copyright: © 2014 Jonathan M. Chase. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Over evolutionary time, multicells change from consisting entirely of germ cells (A) to consisting of a blend of germ and soma cells (D), where germ cells serve as propagules (founders for a new multicell) and soma cells perform the mutagenic work. (A) Germ cells do not perform mutagenic work. (B) Germs cell do perform mutagenic work. (C) A subset of germ cells performs mutagenic work. (D) Soma cells, but not germ cells, perform mutagenic work.
doi:10.1371/journal.pbio.1001859.g001
Much of life on Earth owes its spectacular success to a rather important evolutionary transition—from single-celled organisms to multicellularity—which has occurred independently in many lineages, enabling the differentiation of cells to perform the highly specialized functions that we see in living fungi, plants, and animals. However, whereas all clones of single-celled organisms have a relatively equal chance of dividing and propagating their genes, most multicellular organisms entrust the propagation of their genes to a few select germline cells amidst a sea of non-reproductive somatic cells. At this point, the fitness of individual cells and the fitness of the entire organism become decoupled./.../
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