The main purpose of the present study was to investigate the genetic variability of Nile Tilapia Oreochromis niloticus strains by using microsatellite DNA markers and to compare these data with those previously obtained with single-nucleotide polymorphisms (SNPs). Five mixed-sex strains and four YY-male strains were analyzed. All nine microsatellite loci were polymorphic; the number of unique alleles per locus varied from 6 at UNH216 to 33 at UNH880. Strong correspondence was observed between the level of expected heterozygosity (H_e) or observed heterozygosity and the number of alleles per locus (A) or the number of private alleles. Strains with high levels of heterozygosity typically had higher values of A and the presence of private alleles. In general, mixed-sex strains had higher genetic variability than YY-male strains. Four mixed-sex strains (GIFT, Ismailia Canal, LSA hybrid, and Miami) had the highest level of genetic variability, with mean H_e ranging from 0.630 to 0.798 and mean A ranging from 5.11 to 9.78. Three YY-male strains (Fishgen YY Dark–Group 2, Fishgen YY Red, and Til-Aqua YY) had low genetic variability, with mean H_e ranging from 0.282 to 0.367 and mean A ranging from 1.89 to 3.56. All investigated strains demonstrated low values of the inbreeding coefficient F_IS (from –0.266 to 0.014), suggesting that mating of closely related individuals is being avoided during maintenance of these strains. Pairwise genetic differentiation index F_ST values had a broad range (from 0.0915 to 0.6063), indicating different levels of genetic differentiation between strains. A dendrogram constructed according to shared allele distance showed the existence of two distinct clusters among strains. The present data on genetic variability of Nile Tilapia strains demonstrated substantial similarity with data from a previous study of SNPs in the same populations.

中文翻译：

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由微卫星 DNA 标记确定的尼罗罗非鱼品系遗传变异性

本研究的主要目的是通过使用微卫星 DNA 标记研究尼罗罗非鱼Oreochromis niloticus菌株的遗传变异性，并将这些数据与以前通过单核苷酸多态性 (SNP) 获得的数据进行比较。分析了五个混合性菌株和四个 YY 雄性菌株。所有九个微卫星位点都是多态的；每个基因座的独特等位基因数量从UNH216 的6 个到UNH880的 33 个不等。期望杂（水平之间观察到很强的对应物ħ _ë）或观察杂和的等位基因每个位点的数目（甲) 或私有等位基因的数量。具有高水平杂合性的菌株通常具有较高的A值和私有等位基因的存在。一般来说，混合性菌株比YY-雄性菌株具有更高的遗传变异性。四混合性菌株（GIFT，伊斯梅利亚运河，LSA混合和迈阿密）具有遗传变异的最高水平，平均ħ _Ë范围从0.630至0.798和平均甲范围从5.11至9.78。三YY-雄性株（Fishgen YY暗组2，Fishgen YY红和胡麻-水族YY）具有低的遗传变异性，平均ħ _Ë范围从0.282至0.367和平均甲范围从 1.89 到 3.56。所有研究的品系都显示出近交系数F _{IS 的}低值（从 –0.266 到 0.014），表明在这些品系的维持过程中避免了密切相关的个体的交配。成对遗传分化指数F _ST值具有广泛的范围（从 0.0915 到 0.6063），表明菌株之间的遗传分化水平不同。根据共享等位基因距离构建的树状图显示菌株之间存在两个不同的簇。目前关于尼罗罗非鱼品系遗传变异性的数据与之前对相同种群中 SNP 的研究数据显示出很大的相似性。