Miller Craig T, Glazer Andrew M, Summers Brian R, Blackman Benjamin K, Norman Andrew R, Shapiro Michael D, Cole Bonnie L, Peichel Catherine L, Schluter Dolph, Kingsley David M
Molecular and Cell Biology Department, University of California, Berkeley, California 94720.
Genetics. 2014 May;197(1):405-20. doi: 10.1534/genetics.114.162420. Epub 2014 Mar 19.
Understanding the genetic architecture of evolutionary change remains a long-standing goal in biology. In vertebrates, skeletal evolution has contributed greatly to adaptation in body form and function in response to changing ecological variables like diet and predation. Here we use genome-wide linkage mapping in threespine stickleback fish to investigate the genetic architecture of evolved changes in many armor and trophic traits. We identify >100 quantitative trait loci (QTL) controlling the pattern of serially repeating skeletal elements, including gill rakers, teeth, branchial bones, jaws, median fin spines, and vertebrae. We use this large collection of QTL to address long-standing questions about the anatomical specificity, genetic dominance, and genomic clustering of loci controlling skeletal differences in evolving populations. We find that most QTL (76%) that influence serially repeating skeletal elements have anatomically regional effects. In addition, most QTL (71%) have at least partially additive effects, regardless of whether the QTL controls evolved loss or gain of skeletal elements. Finally, many QTL with high LOD scores cluster on chromosomes 4, 20, and 21. These results identify a modular system that can control highly specific aspects of skeletal form. Because of the general additivity and genomic clustering of major QTL, concerted changes in both protective armor and trophic traits may occur when sticklebacks inherit either marine or freshwater alleles at linked or possible "supergene" regions of the stickleback genome. Further study of these regions will help identify the molecular basis of both modular and coordinated changes in the vertebrate skeleton.
理解进化变化的遗传结构一直是生物学的一个长期目标。在脊椎动物中，骨骼进化极大地促进了身体形态和功能对饮食和捕食等不断变化的生态变量的适应。在这里，我们利用三刺鱼的全基因组连锁图谱来研究许多盔甲和营养性状进化变化的遗传结构。我们鉴定出了100多个控制鳃耙、牙齿、鳃骨、颌骨、背鳍棘和椎骨等连续重复骨骼元素模式的数量性状位点（QTL）。我们利用这大量的QTL来解决关于控制进化种群骨骼差异的位点的解剖学特异性、遗传显性和基因组聚类的长期问题。我们发现，影响连续重复骨骼元素的大多数QTL（76%）具有解剖学区域效应。此外，大多数QTL（71%）至少具有部分加性效应，无论该QTL控制的是骨骼元素的进化丧失还是增加。最后，许多具有高LOD分数的QTL聚集在4号、20号和21号染色体上。这些结果确定了一个可以控制骨骼形态高度特异性方面的模块化系统。由于主要QTL的一般加性和基因组聚类，当三刺鱼在其基因组的连锁或可能的“超级基因”区域继承海洋或淡水等位基因时，保护性盔甲和营养性状可能会同时发生协同变化。对这些区域的进一步研究将有助于确定脊椎动物骨骼模块化和协调变化的分子基础。
