牙鲆三个同源纯系的生长和遗传性状比较

Growth and genetic analysis among three homologous inbred strains of Paralichthys olivaceus

利用同一牙鲆(Paralichthys olivaceus)家系F09119的母本,建立了减数雌核发育系(F1324)、卵裂雌核发育系(F1346)及近交家系(F1313)3个纯系,对3个纯系群体的生长和遗传性状进行比较分析。在受精后85~388 d对3个家系的体长、体宽、体重及成活率进行测定比较,结果显示:F1346生长最快,388 d时体长、体宽和体重分别为(28.89±2.77)cm、(10.00±1.21)cm和(254.91±83.11)g,F1313次之,F1324最慢(P<0.05)。388 d时F1324成活率最高(46.50%),F1313次之(38.00%),F1346最低(26.80%)。F1346、F1324和F1313平均等位基因数(Na)分别为2.0、2.0和2.35,平均有效等位基因数(Ne)分别为1.87、1.95和2.1,多态信息含量(PIC)分别为0.35、0.36和0.4,平均观测杂合度分别为0、0.8155和0.6366;卵裂雌核发育系和减数雌核发育系的遗传多样性明显低于近交系。平均期望纯合度F1313(0.503)<F1324(0.5105)<F1346(0.532);平均期望杂合度正好相反,F1313(0.4967)>F1324(0.4894)>F1346(0.4679)。卵裂雌核发育系纯合度是减数雌核发育系的1.0421倍,是近交系的1.0577倍;减数雌核发育系纯合度是近交系的1.0149倍。F1346与F1313之间的遗传距离最大(0.1568),遗传相似度最小(0.8549);F1346与F1324之间的遗传距离最小(0.0406),遗传相似度最大(0.9602)。本研究结果为牙鲆纯系构建及解析卵裂雌核发育系、减数雌核发育系和近交系的遗传区别提供了理论依据。

Establishing meiotic gynogenesis, mitotic gynogenesis, and inbred lines is important for trait purification during selective fish breeding. Yet how these three genetic pathways affect heredity remains the focus of much genetics research. In this study, we used the female parents from Paralichthys olivaceus family F09119 to establish mitotic gynogenesis （F1346）, meiotic gynogenesis （F1324）, and an inbred line （F1313） and analyzed their growth and genetic characteristics. Body length, body width, and weight were measured in the three families from 85 to 388 d post fertilization （dpf）. Results on 338 dpf showed that growth rate of F1346 was the highest[body length, （28.89±2.77） cm; body width, （10.00±1.21） cm; and weight, （254.91±83.11） g] and that of F1324 was the lowest （P〈0.05）. Survival rate of F1324 on 263 dpf was the highest （46.50%） and that of F1346 was the lowest （26.80%）. The numbers of alleles for mitotic gynogenesis, meiotic gynogenesis, and the inbred line were 2.0, 2.0 and 2.35, respectively. The effective numbers of alleles were 1.87, 1.95, and 2.1; polymorphic information content values were 0.35, 0.36, and 0.4; and mean observed heterozygosity values were 0, 0.8155, and 0.6366, respectively, indicating that genetic variation of mitotic gynogenesis and meiotic gynogenesis was less than that of the inbred line. The trend for unbiased expected homozygosity was F1313 （0.503） 〈 F1324 （0.5105） 〈 F1346 （0.532） and that of unbiased expected heterozygosity was F1313 （0.4967） 〉 F1324 （0.4894） 〉 F1346 （0.4679）. Homozygosity of meiotic gynogenesis was 1.0421-fold higher than that of meiotic gynogenesis and 1.0577-fold higher than that of the inbred line, whereas that of meiotic gynogenesis was 1.0149-fold higher than that of the inbred line. The genetic distance between F1346 and F1313 was longest （0.1568） but genetic similarity was the lowest （0.8549）, whereas the genetic distance between F1346 and F1324 was the shortest （0.0406）, and genetic similarity was the greatest （0.9602）. These results provide a theoretical basis for establishing an inbred line of P. olivaceus and analyses of genetic variations among meiotic gynogenesis, mitotic gynogenesis, and the inbred line.