东南太平洋茎柔鱼种群遗传多样性及其与生境因子的关联

Population genetic diversity of Dosidicus gigas in the Southeastern Pacific Ocean and its relationship with habitat factors

摘要:

为探讨东南太平洋茎柔鱼（Dosidicus gigas）种群遗传多样性及其与生境因子的关系,利用线粒体COⅠ基因,结合冗余分析和Mantel检验,对大、中、小3种表型群体的遗传多样性及生境因子的影响进行分析。结果显示,茎柔鱼群体总体单倍型多样性（Haplotype diversity,H_d）为0.455、核苷酸多样性（Nucleotide diversity,π）为0.001 1,呈现高H_d和低π的特点。群体间遗传分化系数（F_st）小于0.05,基因流（N_m）大于1,群体内变异占比高达99.14%。遗传数据表明,群体曾经历历史扩张事件,时间约为46 700年前。冗余分析和Mantel检验结果显示,群体地理距离与平均遗传距离相关性较弱,纬度（Latitude,lat）、海表面温度（Sea surface temperature,SST）、海面盐度（Sea surface salinity,SSS）、酸碱度（pH）是显著影响茎柔鱼种群遗传多样性的生境因子（P<0.05）,且不同表型群体受不同的生境因子的影响。研究表明,茎柔鱼3种表型群体间未发生显著的遗传分化,生境因子对3种表型群体的遗传多样性具有显著影响。本研究可为保护和管理茎柔鱼种群提供重要参考。

关键词:茎柔鱼;遗传多样性;生境因子;COⅠ基因;东南太平洋

Abstract:

To explore the genetic diversity of Dosidicus gigas in the Southeastern Pacific Ocean and its relationship with environmental factors, this study analyzed the genetic diversity of three phenotypic groups （large, medium, and small） and the impact of environmental factors using mitochondrial COⅠ gene data, redundancy analysis （RDA）, and Mantel tests. The results showed that the overall haplotype diversity （H_d） of D. gigas populations was 0.455, while nucleotide diversity （π） was 0.001 1, indicating high H_d and low π. The genetic differentiation coefficient （F_st） between populations was less than 0.05, gene flow （N_m） was greater than 1, and within-group variation accounted for 99.14% of the total. Genetic data suggested that the populations underwent a historical expansion event approximately 46 700 years ago. RDA and Mantel test results indicated a weak correlation between geographical distance and mean genetic distance, while latitude （lat）, sea surface temperature （SST）, sea surface salinity （SSS）, and pH were significant environmental factors influencing the genetic diversity of D. gigas populations （P<0.05）. Furthermore, the distribution of different phenotypic groups was influenced by distinct environmental factors. The study concluded that there was no significant genetic differentiation among the three phenotypic groups of D. gigas, but environmental factors had a significant impact on their genetic diversity. This research provides valuable reference data for the conservation and management of D. gigas populations.

Key words:Dosidicus gigas;genetic diversity;habitat factors;COⅠgene;the Southeastern Pacific Ocean