Data from: Kin recognition in a clonal fish, Poecilia formosa

Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clonals, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.

亲缘相关性（relatedness）对众多物种的社会行为具有显著影响。对于多数物种而言，典型的最高亲缘相关性通常存在于同父母的全同胞个体之间，二者共享50%的基因。然而，对于个体间亲缘相关性异乎寻常地高的物种——即克隆生物（clonal organisms）——而言，这一规律的相关机制仍有待深入探究。尽管已有针对克隆无脊椎动物与酵母的相关研究，但目前学界对克隆脊椎动物的亲缘选择（kin selection）机制仍一无所知。本研究表明，克隆鱼类亚马逊花鳉（Amazon molly，*Poecilia formosa*）能够区分不同的克隆谱系（clonal lineages），会与基因完全一致的同胞克隆个体建立社交关联，并可利用多种感官模态（sensory modalities）完成识别。此外，该物种的攻击行为强度会根据与其他雌性个体的亲缘相关性进行调节：对非亲缘克隆个体的攻击性更强。本研究结果证实，即便在个体间基因差异极小的物种中，亲缘识别依然可以具有适应性。它们的识别能力以及对高成本行为的调控机制，为遗传多样性有限的物种中的自然选择提供了极具说服力的例证。