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Pastimes : THE SLIGHTLY MODERATED BOXING RING -- Ignore unavailable to you. Want to Upgrade?

To: Poet who wrote (17866)	7/19/2002 11:16:49 AM
From: jlallen	Respond to of 21057

Message 17761291 Message 17760900

To: Poet who wrote (17866)	7/20/2002 11:43:48 PM
From: E	Read Replies (2) \| Respond to of 21057

This is the most interesting thing i've read in a long time. You have to penetrate (so to speak) the scientific prose, but the information is so remarkable (yet not) that it's worth the effort. Subject: Altruistic sperm. When there is sperm from two males in the race, they give up their chance to reproduce themselves, acting to improve the chances of the sperm genetically related to them. 11 July 2002 Nature 418, 174 - 177 (2002); doi:10.1038/nature00832 Exceptional sperm cooperation in the wood mouse HARRY MOORE, KATERINA DVORÁKOVÁ†, NICHOLAS JENKINS & WILLIAM BREED‡ * Section of Reproductive and Developmental Medicine, University of Sheffield, S10 2UH, UK † Department of Developmental Biology, Charles University, Prague 2, 128 44, Czech Republic ‡ Department of Anatomical Sciences, University of Adelaide, South Australia SA5005, Australia Spermatozoa from a single male will compete for fertilization of ova with spermatozoa from another male when present in the female reproductive tract at the same time. Close genetic relatedness predisposes individuals towards altruism, and as haploid germ cells of an ejaculate will have genotypic similarity of 50%, it is predicted that spermatozoa may display cooperation and altruism to gain an advantage when inter-male sperm competition is intense. We report here the probable altruistic behaviour of spermatozoa in an eutherian mammal. Spermatozoa of the common wood mouse, Apodemus sylvaticus, displayed a unique morphological transformation resulting in cooperation in distinctive aggregations or 'trains' of hundreds or thousands of cells, which significantly increased sperm progressive motility. Eventual dispersal of sperm trains was associated with most of the spermatozoa undergoing a premature acrosome reaction. Cells undergoing an acrosome reaction in aggregations remote from the egg are altruistic in that they help sperm transport to the egg but compromise their own fertilizing ability. nature.com