裂腹鱼亚科系统发育与适应性进化及祁连山裸鲤的分类地位  

Phylogenetic and adaptive evolution analysis of Schizothoracinae fish and the taxonomic status of Gymnocypris chilianensis

作　　者：宋丹 彭頔 程起群[1] SONG Dan;PENG Di;CHENG Qiqun(East China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Shanghai 200090,China;College of Fisheries and Life Science,Shanghai Ocean University,Shanghai 201306,China)

机构地区：[1]中国水产科学研究院东海水产研究所,上海200090 [2]上海海洋大学水产与生命学院,上海2013066

出　　处：《中国水产科学》2023年第6期685-698,共14页Journal of Fishery Sciences of China

基　　金：国家自然科学基金项目(32273140)。

摘　　要：裂腹鱼亚科(Schizothoracinae)系统发育和适应性进化机制尚不明确,且祁连山裸鲤(Gymnocyprischilianensis)的分类地位尚存争议。本研究基于所有已公开的裂腹鱼亚科11属65种鱼类的线粒体全基因组序列进行分析,试图为阐明上述问题提供基因组学依据。结果如下:(1)系统发育。研究表明裂腹鱼亚科鱼类不是单系群,其分属于两个不同的支系,每个支系包含若干属种,其中原始类群的裂腹鱼聚为一支,特化类群和高度特化类群的裂腹鱼聚为另一支。(2)适应性进化。以裂腹鱼的分布海拔高度区间为划分标准,分为低、中、高3组,基于分支模型和位点模型的检测结果显示, 13个蛋白编码基因的ω比值都<1,均未检测到正选择位点。但是在氨基酸水平上, Atp6、ND2、ND3、ND4、ND5中均检测出正选择位点,正选择作用主要发生在呼吸链复合物I (NADH-泛醌氧化还原酶)中,线粒体呼吸链又是生物活性氧(ROS)最主要的来源,这可能解释了裂腹鱼亚科对高海拔缺氧环境的适应性进化机制。同时,分歧时间估算结果显示,原始类群裂腹鱼分化于3.200Ma前,特化类群裂腹鱼与高度特化类群裂腹鱼在5.972Ma前至5.320Ma前开始产生分化,处于晚中新世时期。(3)祁连山裸鲤分类地位。基于Kimura双参数模型计算遗传距离,结果表明与祁连山裸鲤遗传距离最近的为柴达木裸裂尻鱼(Schizopygopsiskessleri),遗传距离为0.0015;而祁连山裸鲤与花斑裸鲤(Gymnocypriseckloni)的遗传距离为0.0673,大于0.0600,已经达到了种的分化。从分子水平上明确了祁连山裸鲤为裸鲤属的一个独立种,并非花斑裸鲤的亚种,为解决长期以来祁连山裸鲤分类地位的分歧提供了佐证。Schizothoracinae is an endemic fish of the Tibetan Plateau and its surrounding areas.The phylogenetic and adaptive evolutionary mechanisms of this subfamily are unclear,and the taxonomic status of Gymnocypris chilianensis remains controversial.This study evaluated the complete mitochondrial genome sequences of 65 species of Schizothoracinae in 11 specified genera,with the aim of providing a genomic basis for elucidating the above issues.The corresponding results are as follows:(1)Phylogeny.The results showed that the Schizothoracinae subfamily is not monophyletic but belongs to two different clades,with each taxon containing several generic species.The primitive taxa of the Schizothoracinae fishes were grouped into one clade;the specialized taxa and highly specialized taxa were grouped into another clade;(2)Adaptive evolution.The results showed that no positive selection sites were detected at any of the 13 protein-coding genes withωratios<1.Positive selection sites were also found in Atp6,ND2,ND3,ND4,and ND5.Nonetheless,positive selection primarily occurred in respiratory chain complex I(NADH1-6);the mitochondrial respiratory chain is the most important source of biologically reactive oxygen species(ROS),which may explain the adaptive evolutionary mechanism of the subfamily Schizothoracinae fishes in high-altitude hypoxic environments.For the divergence time study,the divergence time of the primitive taxon Schizothoracinae fishes was estimated to be before 3.200 Ma;the specialized taxon Schizothoracinae fishes began to differentiate between 5.972 Ma and 5.320 Ma in the late Miocene period;(3)Taxonomic status of G.chilianensis.Based on the Kimura two-parameter model,the genetic distance between G.chilianensis and Schizopygopsis kessleri was 0.0015.Nonetheless,the genetic distance between G.chilianensis and Gymnocypris eckloni was 0.0673(>0.0600),indicating species differentiation.Overall,it is clear that,at the molecular level,G.chilianensis is a distinct species of the genus Gymnocypris and not a subspecies of

关 键 词：裂腹鱼亚科 祁连山裸鲤 系统发育 适应性进化 线粒体基因组 

分 类 号：S917[农业科学—水产科学]