Department of Biology, Faculty of Science, Mahasarakham University, Mahasarakham, Thailand.
Heredity (Edinb). 2011 May;106(5):749-56. doi: 10.1038/hdy.2010.115. Epub 2010 Sep 8.
Grouping provides many potential benefits to individuals in terms of foraging and anti-predator protection. However, it has been suggested that individuals could gain additional benefits in terms of indirect fitness by grouping with kin. Surprisingly, the genetic composition of wild fish shoals and the importance of kin-associated shoaling remain poorly understood. The Trinidadian guppy (Poecilia reticulata) has life history traits that might promote kin structure of shoals such as internal fertilisation and small brood size in contrast to many other fish species. Even though previous studies did not find any indication of kin structure in shoals of adult guppies, it is possible that related juveniles remain together in shoals, partly because of lower mobility and because the advantages of kin association may change with age. Using 10 microsatellite markers, we conducted a genetic analysis on 40 shoals from four populations. Pair-wise relatedness was inferred using a modified version of the software package COLONY and permutation tests were conducted to test the hypothesis that kin occur together in juvenile shoals more often than expected by chance. The frequency of sib dyads among juveniles within shoals was significantly larger than that between shoals in two high predation populations but not in two low predation populations. This finding contributes to the understanding of factors underlying shoal composition and highlights the potential of recent methodological advances for detecting such relationships.
分组为个体在觅食和抗捕食保护方面提供了许多潜在的好处。然而，有人认为，通过与亲属群体聚集，个体可以在间接适应度方面获得额外的好处。令人惊讶的是，野生鱼类鱼群的遗传组成以及亲缘相关的鱼群聚集的重要性仍然知之甚少。特立尼达孔雀鱼（Poecilia reticulata）具有一些生活史特征，可能会促进鱼群的亲缘结构，例如体内受精和较小的胚胎大小，与许多其他鱼类物种形成对比。尽管之前的研究没有发现成年孔雀鱼鱼群中存在亲缘结构的任何迹象，但相关的幼鱼可能仍然聚集在一起，部分原因是它们的移动性较低，而且亲缘关系的优势可能会随着年龄的增长而发生变化。我们使用 10 个微卫星标记，对来自四个种群的 40 个鱼群进行了遗传分析。使用 COLONY 软件包的修改版本推断成对的亲缘关系，并进行了随机检验，以检验亲缘关系的个体更经常聚集在幼鱼鱼群中的假设，而不是偶然发生。在两个高捕食压力的种群中，幼鱼在鱼群内的同胞二联体的频率显著大于鱼群间的频率，但在两个低捕食压力的种群中则不然。这一发现有助于理解鱼群组成的基础因素，并强调了最近方法学进展在检测这种关系方面的潜力。
