The insulin/insulin-like growth factor signalling pathway has been hypothesized as a major determinant of life-history profiles that vary adaptively in natural populations. In Drosophila melanogaster, multiple components of this pathway vary predictably with latitude; this includes foxo, a conserved gene that regulates insulin signalling and has pleiotropic effects on a variety of fitness-associated traits. We hypothesized that allelic variation at foxo contributes to genetic variance for size-related traits that vary adaptively with latitude. We first examined patterns of variation among natural populations along a latitudinal transect in the eastern United States and show that thorax length, wing area, wing loading, and starvation tolerance exhibit significant latitudinal clines for both males and females but that development time does not vary predictably with latitude. We then generated recombinant outbred populations and show that naturally occurring allelic variation at foxo, which exhibits stronger clinality than expected, is associated with the same traits that vary with latitude in the natural populations. Our results suggest that allelic variation at foxo contributes to adaptive patterns of life-history variation in natural populations of this genetic model.

中文翻译：

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Foxo的等位基因多态性有助于果蝇的局部适应

胰岛素/胰岛素样生长因子信号通路被假设为在自然群体中适应性变化的生活史特征的主要决定因素。在果蝇中，该途径的多个组成部分可预测地随纬度变化。其中包括Foxo，这是一种保守基因，可调节胰岛素信号传导并对各种健身相关特征具有多效性。我们假设Foxo的等位基因变异会导致大小相关性状的遗传变异，这些性状会随纬度适应性地变化。我们首先研究了美国东部沿纬度横断面的自然种群之间的变异模式，结果表明，雄性和雌性的胸部长度、翅膀面积、翅膀载荷和饥饿耐受性都表现出显着的纬度变化，但发育时间并没有可预测的变化与纬度。然后，我们生成了重组远交群体，并表明 Foxo 自然发生的等位基因变异（其表现出比预期更强的临床性）与自然群体中随纬度变化的相同特征相关。我们的结果表明，foxo的等位基因变异有助于这种遗传模型的自然群体生活史变异的适应性模式。