Vity [7]; according to some, the latter behave in several ways like
Vity [7]; according to some, the latter behave in several ways like germ cells, and especially like sperm [218,219]. ENCODE may have helped to bring to light the exceptional genetic activity of the germline. It is also interesting that new genes have a strong bias of being expressed in the testis, whereas older genes have stronger and broader expression patterns [193,216,220,221]. To explain this bias, it has been suggested that new genes arise first in the sperm to serve sperm functions, and that later these genes are somehow coopted for somatic functions [216,221,222]. This has been called the “out of testis” hypothesis [216,221,222]. Two reasons have been given for why this happens in the sperm specifically: One is the existence of TP there.Interestingly, TP is used in this hypothesis in a manner not far from the above–it is seen there as a phenomenon that facilitates genetic evolutionary OPC-8212MedChemExpress Vesnarinone change–though its origin in the first place is not easily explained from this view. Second, it was assumed that the sperm are under much stronger pressure to evolve rapidly than other cells in the body, and are thus in “high demand” of new genes [212,216]. However, a main reason to think that these new genes really serve the sperm in its performing phenotype is that knockout of them disrupts the development of sperm. According to the traditional theory, which has only the performing phenotype, this evidence of functionality from knockout indeed means that these genes serve the sperm. But the theory proposed here predicts the existence of the writing phenotype, which raises the possibility that many (though not all) of what we think of as “new sperm genes” serving the sperm’s performing phenotype are not necessarily traditional “sperm genes” but are either genes with an evolving somatic function that are the locus of much writing activity or genes that belong to the body of the writing phenotype, and that disruption of them by knockout derails the writing system and makes it cause damage in the sperm cell (indeed, the sensitivity of sperm cells is well known). Thus, the observation that has led to the assumption that the sperm are under pressure for rapid evolutionary change, which has underlain the out-of-testis hypothesis in the first place, may not be only due to rapid evolution of the sperm performing phenotype. It could be that, to a notable degree, the sperm appears to be so rapidly evolving because of the writing activity in it and the evolution of this activity. Indeed, we may now note that, of the examples of adaptive evolution detected by dN/dS > 1 mentioned in [223], the first two (and in that sense prominent) categories of examples mentioned involve molecular environment interaction genes and rapid evolution of sperm, and both of these take on entirely new meaning according to the theory proposed here. Though much more data are needed on the material discussed in this section, one thing we need to notice is that the “working sperm” hypothesis has relevance beyond science. In 2001, Old [218] (see also [219]) suggested that cancer cells imitate germ cells and trophoblasts in several respects which appear to be part of the malignancy of PubMed ID: the disease, including global hypomethylation, expression of cancer-testis (CT) antigens, expression of chorionic gonadotropin, downregulation of the major histocompatibility complex and immune evasion, and more. Indeed, cancer cells are exceptionally genetically active. We should ask, therefore, whether ac.