Ecological Genetic Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland.
PLoS One. 2012;7(7):e39843. doi: 10.1371/journal.pone.0039843. Epub 2012 Jul 6.
The estimation of individual fitness and quality are important elements of evolutionary ecological research. Over the past six decades, there has been great interest in using fluctuating asymmetry (FA) to represent individual quality, yet, serious technical problems have hampered efforts to estimate the heritability of FA, which, in turn, has limited progress in the investigation of FA from an evolutionary perspective. Here we estimate the heritability of number of lateral plates, their FA and directional asymmetry (DA) in threespine stickleback, Gasterosteus aculeatus. By (i) using a meristic trait and (ii) basing our calculations on a large half-sib design experiment involving 2,079 offspring from 84 families, we overcame many of the difficulties faced by earlier FA studies. Both lateral plate number and FA in lateral plates were heritable (h(2) = 0.46 and 0.21, respectively), even after controlling for marker genotypes linked to EDA (the major locus influencing plate number). Likewise, DA in lateral plates was heritable h(2) = 0.23). The additive genetic component of FA in lateral plates makes it a prime candidate for further investigation into the evolutionary implications of FA and the genetic underpinnings of developmental instability. This discovery in an evolutionary model species holds the possibility to invigorate the study of FA from an evolutionary perspective.
个体适合度和质量的估计是进化生态学研究的重要组成部分。在过去的六十年中，人们对使用波动不对称（FA）来代表个体质量产生了浓厚的兴趣，但严重的技术问题阻碍了对 FA 遗传力的估计，这反过来又限制了从进化角度对 FA 的研究进展。在这里，我们估计了三刺鱼，棘鱼的侧板数量，其 FA 和方向不对称（DA）的遗传力。通过（i）使用一个可数性状，和（ii）基于涉及 84 个家庭的 2079 个后代的大半同胞设计实验，我们克服了早期 FA 研究面临的许多困难。侧板数量和侧板中的 FA 都是可遗传的（h²分别为 0.46 和 0.21），即使在控制与 EDA 相关的标记基因型（影响板数量的主要基因座）后也是如此。同样，侧板中的 DA 也是可遗传的（h²=0.23）。侧板中 FA 的加性遗传成分使其成为进一步研究 FA 的进化意义和发育不稳定性遗传基础的首选候选者。这一在进化模式物种中的发现有可能为从进化角度研究 FA 带来新的活力。
