The genetic architecture of novel trophic specialists: higher effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation

The genetic architecture of adaptation is fundamental to understanding the mechanisms and constraints governing diversification. However, most case studies focus on loss of complex traits or parallel speciation in similar environments. It is still unclear how the genetic architecture of these local adaptive processes compares to the architecture of evolutionary transitions contributing to morphological and ecological novelty. Here we identify quantitative trait loci (QTL) between two trophic specialists in an excellent case study for examining the origins of ecological novelty: a sympatric radiation of pupfishes endemic to San Salvador Island, Bahamas containing a large-jawed scale-eater and a short-jawed molluscivore with a skeletal nasal protrusion. These specialized niches and trophic traits are unique among over 2,000 related species. Measurements of the fitness landscape on San Salvador demonstrate multiple fitness peaks and a larger fitness valley isolating the scale-eater from th...

适应性遗传结构（genetic architecture）是解析调控物种分化的机制及其约束条件的核心基础。然而，现有多数案例研究多聚焦于复杂性状的丢失或相似环境下的平行物种形成。目前仍不清楚，这类局部适应性过程的遗传结构，与驱动形态与生态新特征产生的演化过渡过程的遗传结构存在何种差异。本研究依托一项用于探究生态新性状起源的典范案例，在两种营养特化类群间定位了数量性状位点（quantitative trait loci, QTL）：该案例为巴哈马圣萨尔瓦多岛特有的同域辐射演化鳉鱼类群，包含颌骨宽大的食鳞者与带有骨骼鼻部突起的短颌软体动物捕食者。在超过2000个近缘物种中，这类特化生态位与营养性状均属独有。对圣萨尔瓦多岛的适合度景观进行的测量显示，存在多个适合度峰，以及一道将食鳞者与[原文未完结]