Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
J Evol Biol. 2010 Apr;23(4):783-90. doi: 10.1111/j.1420-9101.2010.01948.x. Epub 2010 Feb 12.
When phenotypic change occurs over time in wildlife populations, it can be difficult to determine to what degree it is because of genetic effects or phenotypic plasticity. Here, we assess phenotypic changes over time in horn length and volume of thinhorn sheep (Ovis dalli) rams from Yukon Territory, Canada. We considered 42 years of horn growth from over 50,000 growth measurements in over 8000 individuals. We found that weather explained a large proportion of the annual fluctuation in horn growth, being particularly sensitive to spring weather. Only 2.5% of variance in horn length growth could be explained by an individual effect, and thus any genetic changes over the time period could only have had a small effect on phenotypes. Our findings allow insight into the capacity for horn morphology to react to selection pressures and demonstrate the overall importance of climate in determining growth.
当野生动物种群的表型随着时间发生变化时，很难确定它在多大程度上是由于遗传效应或表型可塑性造成的。在这里，我们评估了加拿大育空地区的瘦角羚羊公羊角长和角体积随时间的变化。我们考虑了 42 年来超过 50,000 次生长测量，涉及超过 8000 个个体。我们发现，天气解释了角生长年度波动的很大一部分，对春季天气特别敏感。只有 2.5%的角长生长方差可以用个体效应来解释，因此在这段时间内的任何遗传变化只能对表型产生很小的影响。我们的研究结果使我们能够深入了解角形态对选择压力的反应能力，并展示了气候在决定生长方面的总体重要性。
