The family Cyprinidae is widely distributed in East Asia, and has the important phylogenetic signifi- cance in the fish evolution. In this study, the 5′ end partial sequences (containing exon 1, exon 2 and indel 1) of S6K1 gene were obtained from 30 representative species in Cyprinidae and outgroup using PCR amplification and sequencing. The phylogenetic relationships of Cyprinidae were reconstructed with neighbor joining (NJ), maximum parsimony (MP), maximum likelihood (ML), and Bayesian meth- ods. Myxocyprinus asiaticus (Catostomidae) was assigned to the outgroup taxon. Similar phylogenetic relationships within the family Cyprinidae were achieved with the four analyses. Leuciscini and Barbini were monophyletic lineages respectively with the high nodal supports. Leuciscini comprises Hy- pophthalmichthyinae, Xenocyprinae, Cultrinae, Gobioninae, Acheilognathinae and East Asian species of Leuciscinae and Danioninae. Monophyly of East Asian clade was supported with high nodal support. Barbini comprises Schizothoracinae, Barbinae, Cyprininae and Labeoninae. The monophyletic lineage consisting of Danio rerio, D. myersi, and Rasbora trilineata was basal in the tree. In addition, the large fragment indels in intron 1 were analyzed to improve the understanding of Cyprinidae relationships. The results showed that the large fragment indels were correlated with the relations among species. Some conserved regions in intron 1 were thought to be involved in the functional regulation. However, no correlation was found between sequence variations and species characteristic size.
KONG XiangHui1,2, WANG XuZhen1, GAN XiaoNi1, LI JunBing1 & HE ShunPing1 1 Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
鲤科鱼类在东亚分布广泛且数量丰富,在物种演化上具有重要的系统发育地位.本研究基于S6K1基因5′端功能调控序列,通过PCR扩增、克隆和测序,共获得30种鱼类S6K1前端部分DNA序列(外显子1,外显子2及内含子1),对序列变异进行分析,并采用邻接法(NJ)、最大简约法(MP)、最大似然法(ML)和贝叶斯法(Bayesian)重建鲤科鱼类系统发育关系.亚口鱼科的胭脂鱼(Myxocyprinus asiaticus)作为外类群,通过4种方法所得系统发育分支图大致相同,均以较高的节点支持率支持雅罗鱼系和鲃系的划分,雅罗鱼系包括雅罗鱼亚科东亚类群(East Asian group in Leuciscinae)、鲢亚科(Hypophthalmichthyinae)、鲴亚科(Xenocyprinae)、鲌亚科(Cultrinae)、亚科(Gobioninae)、鳑鲏亚科(Acheilognathinae)和亚科(Danioninae)部分种类;系统分支图也以较高的节点支持率支持鲤科鱼类东亚类群形成单系群.鲃系包括裂腹鱼亚科(Schizothoracinae)、鲃亚科(Barbinae)、鲤亚科(Cyprininae)和野鲮亚科(Labeoninae);另外,亚科中的斑马鱼(Danio rerio),麦氏(Danio myersi)和三线波鱼(Rasbora trilineata)形成一个单系群,位于系统树基部.以内含子1中大片段的插入或缺失(Indel)对物种分化及亲缘关系进行分析,以帮助理解鲤科鱼类系统发育关系或争议物种之间的亲缘关系.结果显示,内含子1中大片段的插入或缺失与物种分化具有一定的相关性,对于理解系统发育关系具有补充作用;内含子1中有许多区域较为保守,可能与功能调控有关,但本研究中并未发现S6K1序列变异与鱼类物种特征尺寸之间具有对应关系.
The family Cyprinidae is one of the largest fish families in the world,which is widely distributed in East Asian,with obvious difference in characteristic size among species. The phylogenetic analysis of cy-prinid taxa based on the functionally important genes can help to understand the speciation and functional divergence of the Cyprinidae. The c-myc gene is an important gene regulating individual growth. In the present study,the sequence variations of the cyprinid c-myc gene and their phylogenetic significance were analyzed. The 41 complete sequences of the c-myc gene were obtained from cyprinids and outgroups through PCR amplification and clone. The coding DNA sequences of the c-myc gene were used to infer molecular phylogenetic relationships within the Cyprinidae. Myxocyprinus asiaticus (Catostomidae),Misgurnus anguillicaudatus (Cobitidae) and Hemimyzon sinensis (Homalopteridae) were assigned to the outgroup taxa. Phylogenetic analyses using maximum parsimony (MP). maximum likelihood (ML),and Bayesian retrieved similar topology. Within the Cyprinidae,Leuciscini and Barbini formed the monophyletic lineage respectively with high nodal supports. Leuciscini comprises Xeno-cyprinae,Cultrinae,East Asian species of Leuciscinae and Danioninae,Gobioninae and Acheilog-nathinae,and Barbini contains Schizothoracinae,Barbinae,Cyprininae and Labeoninae. Danio rerio,D. myersi and Rasbora trilineata were supposed to separate from Leuciscinae and Barbini and to form another lineage. The positions of some Danioninae species were still unresolved. Analyses of both amino acid variation with parsimony information and two high variation regions indicated that there is no correlation between variations of single amino acid or high variation regions and characteristic size of cyprinids. In addition,the species with smaller size were usually found to be basal within clades in the tree,which might be the results of the adaptation to the primitive ecology and survival pressure.
