河川沙塘鳢繁殖期与非繁殖期种群形态差异、雌雄个体差异及遗传多样性分析

Morphological differences,individual differences between male and female,and genetic diversity analysis of reproductive and nonreproductive populations of Odontobutis potamophilus

本研究利用传统形态性状测量及框架性状分析方法研究了江苏省河川沙塘鳢繁殖期与非繁殖期种群形态特征及雌雄个体差异。结果显示,河川沙塘鳢存在形态特征的季节差异,繁殖期个体拥有相对较大的眼径、眼间距,推测与食物资源的季节性变化有关;另外,背鳍前距和胸鳍基长较长,可能因性腺发育饱满导致该时期个体腹腔容积变大。在两性特征中,两性异形指数为-0.013,表明雄鱼个体较大。雄性在尾柄高、尾鳍长等方面显著大于雌性,以此来增加竞争能力以及对后代的保护能力。雌性个体具有较大的腹腔容量,增加了繁殖输出,提高繁殖适合度。另外,本研究基于线粒体cyt b基因,84个个体共识别出17个单倍型,整体表现出具有较高的遗传多样性(h=0.892,π=0.508%),表明江苏省河川沙塘鳢群体存在丰富的线粒体DNA多态性。

Morphological differences of Odontobutis potamophilus during reproduction and non⁃reproduction periods and the discrimination of male and female were investigated using samples collected in Jiangsu Province by traditional mor⁃phological character measurement and truss analysis methods.Results indicated that a distinct seasonal variation occurred in O.potamophilus.Individuals had larger eye diameter and interorbital width during reproduction period,which might be related to food resource availability.Individuals in this period also had larger pre⁃dorsal length and pectoral fin base length,likely associated with the increasing capacity of abdominal cavity as a result of gonadal maturity.The sexual di⁃morphism index was-0.013,indicating a significant sexual dimorphism in body size,with males larger than females.Males had larger caudal peduncle depth and caudal fin length than females,which could be advantageous in competition for spouses and protection of offspring.Females increased individual fecundity by increasing the capacity of abdominal cav⁃ity.Furthermore,17 haplotypes were derived from 84 individuals of O.potamophilus based on cyt b gene analysis.High haplotype diversity and high nucleotide diversity were detected(h=0.892,π=0.508%),suggesting that there are abun⁃dant mitochondrial DNA polymorphisms in O.potamophilus populations.