The genetic architecture of novel trophic specialists: larger effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation
The genetic architecture of novel trophic specialists: larger effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation
复制标题
新型营养专家的遗传结构：较大的效应大小与鳉鱼适应性辐射中特殊的口颌多样化有关
作者：
C. Martin;Priscilla A. Erickson;Craig T. Miller
适应的遗传结构对于理解多样化的机制和限制至关重要。然而，大多数案例研究都集中在相似环境中复杂性状的丧失或平行物种形成。目前还不清楚这些局部适应过程的遗传结构与有助于形态和生态新颖性的进化转变的结构相比如何。在这里，我们在一个优秀的案例研究中确定了两个营养专家之间的数量性状位点（QTL），以检验生态新颖性的起源：巴哈马圣萨尔瓦多岛特有的鳉鱼的同域辐射，其中包括一种大颌食鳞动物和一种具有骨骼鼻突出的短颌软体动物。这些特殊的生态位和营养特征在 2000 多个相关物种中是独一无二的。对圣萨尔瓦多适应度景观的测量表明，存在多个适应度峰值和更大的适应度谷，将食鳞者与通才的假定祖先中间表型隔离开来，这表明更大效应的 QTL 应该有助于其独特的表型。我们使用这些专家之间的 F2 杂交来评估这一预测。我们提出了第一个河豚鱼连锁图谱，并检测了性别和八个骨骼特征的显着 QTL。大效应QTL对食鳞动物下颌增大的贡献大于软体动物鼻突出，这与适应性景观的预测一致。口颌大效应QTL的微进化遗传结构与在宏观进化时间尺度上观察到的圣萨尔瓦多辐射内口颌的异常多样化率相似，并且可能促进了该系统中异常的营养新颖性。
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 2000 related species. Measurements of the fitness landscape on San Salvador demonstrate multiple fitness peaks and a larger fitness valley isolating the scale‐eater from the putative ancestral intermediate phenotype of the generalist, suggesting that more large‐effect QTL should contribute to its unique phenotype. We evaluated this prediction using an F2 intercross between these specialists. We present the first linkage map for pupfishes and detect significant QTL for sex and eight skeletal traits. Large‐effect QTL contributed more to enlarged scale‐eater jaws than the molluscivore nasal protrusion, consistent with predictions from the adaptive landscape. The microevolutionary genetic architecture of large‐effect QTL for oral jaws parallels the exceptional diversification rates of oral jaws within the San Salvador radiation observed over macroevolutionary timescales and may have facilitated exceptional trophic novelty in this system.
适应的进化遗传学：模拟研究。
DOI：
10.1017/s0016672399004164
发表时间：
1999
期刊：
Genetical research
影响因子：
--
作者：
Orr,HA
通讯作者：
Orr,HA