What prevents generalists from displacing specialists, despite obvious competitive advantages of utilizing a broad niche? The classic genetic explanation is antagonistic pleiotropy: genes underlying the generalism produce 'jacks-of-all-trades' that are masters of none. However, experiments challenge this assumption that mutations enabling niche expansion must reduce fitness in other environments. Theory suggests an alternative cost of generalism: decreased evolvability, or the reduced capacity to adapt. Generalists using multiple environments experience relaxed selection in any one environment, producing greater relative lag load. Additionally, mutations fixed by generalist lineages early during their evolution that avoid or compensate for antagonistic pleiotropy may limit access to certain future evolutionary trajectories. Hypothesized evolvability costs of generalism warrant further exploration, and we suggest outstanding questions meriting attention.

中文翻译：

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生态位扩张的可进化性成本。

尽管利用广泛的利基市场具有明显的竞争优势，是什么阻止通才替代专家？遗传学上的经典解释是对抗性多效性：普遍性基础的基因产生了“万无一失”的杰作。但是，实验对以下假设提出了挑战：启用小生境扩展的突变必须降低在其他环境中的适应性。理论提出了普遍主义的另一种代价：可进化性降低，或适应能力降低。使用多种环境的通才可以在任何一种环境中进行轻松选择，从而产生较大的相对滞后负载。此外，由通才谱系在进化过程中早期避免或补偿拮抗多效性的固定突变可能会限制进入某些未来进化轨迹的途径。