Selection for high gamete encounter rates explains the success of male and female mating types
Selection for high gamete encounter rates explains the success of male and female mating types
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DOI：
10.1006/jtbi.1999.1017
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发表时间：
2000-01-07
影响因子：
2
通讯作者：
Dusenbery, DB
中科院分区：
文献类型：
--
作者：
Dusenbery, DB
许多小型真核生物通过融合相似的配子(同配子)进行有性繁殖。在没有可区分的精子和卵子的情况下，雄性和雌性交配类型缺失。然而，雄性和雌性截然不同的物种已经如此繁荣，以至于几乎所有熟悉的动植物都有这些交配类型。为什么涉及精子和卵子的有性繁殖如此成功？答案是通过考虑配子之间相遇几率的物理限制而得到的。一个建立在良好关系基础上的生物物理模型为配子大小的进化以及运动性和信息素产生之间的能量分配产生了合适的图景。这些景观表明，高配子相遇率的选择有利于大的、产生信息素的卵子和小的、能动的精子。因此，有雄性和雌性的广播产卵种群可以在较低的种群密度下繁殖，并在缺乏雄性和雌性的种群灭绝的条件下生存。似乎对配子相遇率的物理限制足以解释在真核生物的几个谱系中观察到的同性受精->；内部受精进化序列的前两个步骤。与以前的模型不同的是，不需要假设受精卵的适合度或游泳速度随着配子大小的增加而下降。(C)2000年学术出版社。
Sexual reproduction occurs in many small eukaryotes by fusion of similar gametes (isogamy). In the absence of distinguishable sperm and eggs, male and female mating types are missing. However, species with distinct males and females have so prospered that almost all familiar plants and animals have these mating types. Why has sexual reproduction involving sperm and eggs been so successful? An answer is obtained by considering physical limitations on encounter rates between gametes. A biophysical model based on well-established relationships produces fitness landscapes for the evolution of gamete size and energy allocation between motility and pheromone production. These landscapes demonstrate that selection for high gamete encounter rates favors large, pheromone-producing eggs and small, motile sperm. Thus, broadcast-spawning populations with males and females can reproduce at lower population densities and survive under conditions where populations lacking males and females go extinct. It appears that physical constraints on gamete encounter rates are sufficient to explain the first two steps in the isogamy --> anisogamy --> oogamy --> internal fertilization evolutionary sequence observed in several lineages of the eukaryotes. Unlike previous models, assumptions concerning zygote fitness or decreasing speed of swimming with increasing gamete size are not required. (C) 2000 Academic Press.