Yamanoue Yusuke, Miya Masaki, Matsuura Keiichi, Sakai Harumi, Katoh Masaya, Nishida Mutsumi
Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639, Japan.
Mol Phylogenet Evol. 2009 Jan;50(1):179-89. doi: 10.1016/j.ympev.2008.10.016. Epub 2008 Nov 5.
Balistoid fishes have a unique and reduced pelvic fin structure, which does not exhibit paired structures. The pelvic complex exhibits reductive trends, but its rudimentary structure was retained among balistoids, and its unidirectional and parsimonious reduction in more derived lineages has been hypothesized based on morphology. We investigated the evolution of pelvic complex reduction in balistoids using whole mitochondrial genome (mitogenome) data from 33 species (27 newly determined during the study) that represent the entire morphological diversity of balistoids. Partitioned maximum likelihood and Bayesian analyses were conducted with two datasets that comprised concatenated nucleotide sequences from 13 protein-coding genes (all positions included; third codon positions converted into purine [R] and pyrimidine [Y] [RY-coding]) plus 22 transfer RNA and two ribosomal RNA genes. The resultant trees were well resolved and largely congruent, with most internal branches having high support values. The mitogenomic datasets strongly supported monophylies of both balistids and monacanthids, but rejected previous hypotheses on the intra-relationships in each family. The present tree topology revealed that highly reduced pelvic complexes had multiple origins, and optimization of the traits on the resultant tree strongly suggested the non-unidirectional and independent reduction of pelvic complexes in balistoids. The evolution of balistoid pelvic structure is very different among fishes that exhibit its reductive trends, and this uniqueness in pelvic evolution may be a link to their reproductive behaviors.
鲀形目鱼类具有独特且简化的腹鳍结构，不呈现成对结构。腹鳍复合体呈现出简化趋势，但其基本结构在鲀形目鱼类中得以保留，基于形态学推测，在更多衍生谱系中其具有单向且简约的简化过程。我们利用来自33个物种（研究期间新测定了27个）的全线粒体基因组（线粒体基因组）数据，研究了鲀形目鱼类腹鳍复合体简化的进化过程，这些物种代表了鲀形目鱼类的全部形态多样性。使用两个数据集进行了分区最大似然法和贝叶斯分析，这两个数据集包含来自13个蛋白质编码基因（包括所有位点；第三密码子位点转换为嘌呤[R]和嘧啶[Y][RY编码]）加上22个转运RNA和两个核糖体RNA基因的串联核苷酸序列。得到的树状图解析良好且基本一致，大多数内部分支具有较高的支持值。线粒体基因组数据集强烈支持鲀科和单角鲀科的单系性，但否定了先前关于每个科内部关系的假设。当前的树状拓扑结构表明，高度简化的腹鳍复合体有多个起源，在得到的树上对性状进行优化强烈表明鲀形目鱼类的腹鳍复合体存在非单向且独立的简化过程。在呈现出简化趋势的鱼类中，鲀形目鱼类腹鳍结构的进化非常不同，这种腹鳍进化的独特性可能与其繁殖行为有关。
