具有親屬關系的動物會互助是常見現(xiàn)象，而《自然》雜志網站20日刊登的一項最新研究顯示,，精子之間也存在這種行為,，相同來源的精子會像火車車廂一樣彼此連在一起，從而加快向前游進的速度,。
美國哈佛大學研究人員報告說,，如果將兩種實驗鼠的精子混合在一起，那么相同來源的精子就會利用其頭部的鉤狀物互相連接起來,，協(xié)力向前游動,，這樣一列“精子火車”的速度比單個精子要快約50％，四分之三相同來源的精子都會加入這樣的隊列中。
精子之間的互助行為還不止于此,，在一列“精子火車”中,，會有一些精子提前啟動與卵子進行反應的機制，這一行為會加速整個“列車”的速度,，但是也會導致前者提前死亡。雖然最終只有一個精子能與卵細胞結合,，但如果是同一來源的精子勝出,，一些精子的自我犧牲行為便體現(xiàn)了價值。
哈佛大學研究人員在下一階段將關注精子是采取何種方式來進行彼此間的身份識別,。（生物谷Bioon.com）
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生物谷推薦原始出處：
Nature advance online publication 20 January 2010 | doi:10.1038/nature08736
Competition drives cooperation among closely related sperm of deer mice
Heidi S. Fisher1,2 & Hopi E. Hoekstra1,2
1 Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology,
2 Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138, USA
Correspondence to: Heidi S. Fisher1,2 Correspondence and requests for materials should be addressed to H.S.F.
Among the extraordinary adaptations driven by sperm competition is the cooperative behaviour of spermatozoa1. By forming cooperative groups, sperm can increase their swimming velocity and thereby gain an advantage in intermale sperm competition1, 2. Accordingly, selection should favour cooperation of the most closely related sperm to maximize fitness3. Here we show that sperm of deer mice (genus Peromyscus) form motile aggregations, then we use this system to test predictions of sperm cooperation. We find that sperm aggregate more often with conspecific than heterospecific sperm, suggesting that individual sperm can discriminate on the basis of genetic relatedness. Next, we provide evidence that the cooperative behaviour of closely related sperm is driven by sperm competition. In a monogamous species lacking sperm competition, Peromyscus polionotus, sperm indiscriminately group with unrelated conspecific sperm. In contrast, in the highly promiscuous deer mouse, Peromyscus maniculatus, sperm are significantly more likely to aggregate with those obtained from the same male than with sperm from an unrelated conspecific donor. Even when we test sperm from sibling males, we continue to see preferential aggregations of related sperm in P. maniculatus. These results suggest that sperm from promiscuous deer mice discriminate among relatives and thereby cooperate with the most closely related sperm, an adaptation likely to have been driven by sperm competition.
