Post‐mating reproductive barriers in two unidirectionally hybridizing sunfish (Centrarchidae: Lepomis)
Post‐mating reproductive barriers in two unidirectionally hybridizing sunfish (Centrarchidae: Lepomis)
复制标题
两种单向杂交翻车鱼（Centrarchidae：Lepomis）的交配后生殖障碍
DOI：
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发表时间：
2011
影响因子：
2.1
通讯作者：
J. Epifanio
中科院分区：
文献类型：
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作者：
Simone Immler;Matthew B. Hamilton;N. J. Poslusny;T. R. Birkhead;J. Epifanio
物种间生殖障碍进化过程中事件的进化顺序是物种形成生物学的核心。当交配前障碍失败时，交配后障碍，如同种精子优先（CSP），配子不相容性（GI）和杂交无效性（HI）可能会演变为防止生产（通常）昂贵的杂交后代，降低健身。我们测试了两种太阳鱼物种[蓝鳃太阳鱼（BG）Lepomis macrochirus和南瓜籽太阳鱼（PS）Lepomis gibbosus]及其第一代杂交种之间生殖隔离的交配后机制的作用。进行体外精子竞争实验，我们观察到当BG和PS精子竞争PS卵子时，不对称CSP是主要的交配后分离机制，而当两个物种的精子竞争BG卵子时，则是HI。此外，杂交精子--尽管在没有竞争的情况下是可育的--在竞争中被双亲中的任何一个物种的精子击败。这一结果至少可以部分解释以前的观察，自然杂交在研究系统中是单向的。
The evolutionary sequence of events in the evolution of reproductive barriers between species is at the core of speciation biology. Where premating barriers fail, post‐mating barriers, such as conspecific sperm precedence (CSP), gamete incompatibility (GI) and hybrid inviability (HI) may evolve to prevent the production of (often) costly hybrid offspring with reduced fitness. We tested the role of post‐mating mechanisms for the reproductive isolation between two sunfish species [bluegill (BG) Lepomis macrochirus and pumpkinseed (PS) Lepomis gibbosus] and their first‐generation hybrids. Performing in vitro sperm competition experiments, we observed asymmetric CSP as main post‐mating isolation mechanism when BG and PS sperm were competing for PS eggs, whereas when sperm from both species were competing for BG eggs it was HI. Furthermore, hybrid sperm – although fertile in the absence of competition – were outcompeted by sperm of either parental species. This result may at least partly explain previous observations that natural hybridization in the study system is unidirectional.