THE EVOLUTION OF TRADE‐OFFS: EFFECTS OF INBREEDING ON FECUNDITY RELATIONSHIPS IN THE CRICKET GRYLLUS FIRMUS
THE EVOLUTION OF TRADE‐OFFS: EFFECTS OF INBREEDING ON FECUNDITY RELATIONSHIPS IN THE CRICKET GRYLLUS FIRMUS
复制标题
权衡的演变：近交对蟋蟀繁殖力关系的影响
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Marc A. Derose
中科院分区：
文献类型：
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作者：
D. Roff;Marc A. Derose
特征的进化是由它们之间的相互关系调节的，特别是当这些关系导致适应性权衡时。在本文中，我们探讨了遗传结构对性状之间功能关系的影响。具体来说，我们解决了近亲繁殖对这些关系的影响。我们表明，如果任一性状不存在显性遗传方差，则两个性状之间的线性回归不会受到影响，而如果仅一个性状存在显性遗传方差，则回归的截距而不是斜率会改变。我们使用板球蟋蟀的繁殖力关系来检验后一个假设。谱系分析和近交实验的数据表明，繁殖力存在显着的显性遗传变异，但头部宽度（身体大小的指标）或背纵肌（DLM）质量则没有。繁殖力随着头部宽度的增加而增加，但随着 DLM 质量的增加而减少。正如预测的那样，这两个形态性状的繁殖力回归截距随着近交而减小，但斜率几乎没有变化。坚强蝼蛄是翅二态性的，其中大翅（LW）变种的繁殖力低于小翅（SW）变种。我们假设生育力的差异主要是由于 LW 雌性 DLM 维持（即质量）和产蛋之间对资源的竞争造成的。因此，我们预测每个变体的繁殖力应随近交系数以相同的速率线性下降。其结果将是两个变体的相对适应性发生变化，SW变体的相对适应性随着近交而增加。这一预测得到了支持。这些结果表明，权衡将会演变，这种变化将通过改变适应度成分之间的关系模式来影响进化轨迹。
The evolution of traits is modulated by their interrelationships with each other, particularly when those relationships result in a fitness trade‐off. In this paper we explore the consequences of genetic architecture on functional relationships between traits. Specifically, we address the consequences of inbreeding on these relationships. We show that the linear regression between two traits will not be affected if there is no dominance genetic variance in either trait, whereas the intercept but not the slope of the regression will change if there is dominance genetic variance in one trait only. We test the latter hypothesis using fecundity relationships in the cricket Gryllus firmus. Data from pedigree analysis and an inbreeding experiment show that there is significant dominance genetic variance in fecundity, but not head width (an index of body size) or dorsal longitudinal muscle (DLM) mass. Fecundity increases with head width, but decreases with DLM mass. As predicted, the intercepts of the regressions of fecundity on these two morphological traits decrease with inbreeding, but there is little or no change in slope. Gryllus firmus is wing dimorphic, with the macropterous (LW) morph having a lower fecundity than the micropterous (SW) morph. We hypothesize that the difference in fecundity arises primarily because of a competition for resources in the LW females between DLM maintenance (i.e., mass) and egg production. As a consequence, we predict that the fecundity within each morph should decline linearly with the inbreeding coefficient at the same rate in both morphs. The result of this will be a change in the relative fitness of the two morphs, that of the SW morph increasing with inbreeding. This prediction is supported. These results indicate that trade‐offs will evolve and such changes will affect evolutionary trajectories by altering the pattern of relationships among fitness components.