The Prisoner's Dilemma and polymorphism in yeast SUC genes
The Prisoner's Dilemma and polymorphism in yeast SUC genes
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DOI：
10.1098/rsbl.2003.0083
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发表时间：
2004-02-07
影响因子：
4.7
通讯作者：
Travisano, M
中科院分区：
文献类型：
--
作者：
Greig, D;Travisano, M
单细胞酵母酿酒酵母的SUC多基因家族是多态的，基因的数量和活性都不同。所有的基因编码转化酶，一种分泌的酶，消化细胞外的蔗糖。这种集体努力创造了单个细胞通过窃取邻居消化的糖而不贡献酶本身来背叛（欺骗）的可能性。我们测量了健身的叛逃者，与删除suc2基因，相对于其他同基因的合作者，与功能SUC2基因。我们通过改变人口密度来操纵社区内的社会互动水平，发现叛逃者在低社会性水平下比合作者更不适合，但在密集的社区中更适合。我们认为，选择反社会作弊的原因SUC多态性的性质。臭名昭著的囚徒困境游戏表明，社会行为通常是不稳定的，合作和背叛的成功可能在时间和空间上不断变化。SUC基因的变化反映了对不断变化的生物环境的不断适应，这是合作不稳定的结果。有趣的是，社会互动可以对分子进化产生直接影响，即使是在像酵母这样简单的有机体中。
The SUC multigene family of the single-celled yeast Saccharomyces cerevisiae is polymorphic, with genes varying both in number and activity. All of the genes encode invertase, an enzyme that is secreted to digest sucrose outside of the cell. This communal endeavour creates the potential for individual cells to defect (cheat) by stealing the sugar digested by their neighbours without contributing the enzyme themselves. We measured the fitness of a defector, with a deleted suc2 gene, relative to an otherwise isogenic cooperator, with a functional SUC2 gene. We manipulated the level of social interaction within the community by varying the population density and found that the defector is less fit than the cooperator at low levels of sociality but more fit in dense communities. We propose that selection for antisocial cheating causes SUC polymorphism in nature. The infamous Prisoner's Dilemma game shows that social behaviour is generally unstable, and the success of both cooperation and defection can vary continuously in time and space. The variation in SUC genes reflects constant adaptation to an ever-changing biotic environment that is a consequence of the instability of cooperation. It is interesting that social interactions can have a direct effect on molecular evolution, even in an organism as simple as yeast.