The pattern of geographic variation in karyotypes and mitochondrial DNA in chromosomal hybrid zones of Nelima nigricoxa (Arachnida, Opiliones)

为了揭示黑脉金线虫染色体杂交带的性质和形成过程，我们分析了该物种不同种群及其近缘同源物的核型、等位酶和mtDNA。Nlima nigricoxa共识别出7种核型：2n=20(朝日河以西的九州、四国和初国地区)，2n=18a(大仙山、鸟取县和近海地区以西)，2n=18b(冈山市以北)，2n=16(朝日河以东的楚国山脉)，2n=22a(伊豆-箱根)，2n=22b(三浦半岛)，2n=22c(千叶岛清水山)。其中，相邻的三对核型(2n=20/18a、2n=18a/16和2n=16/18a)形成一个宽度小于1-3千米的杂交带。在鸟取县关根町2n=16-18a杂交区的群体(Shimimu-Dani)中，具有2n=17条染色体的个体比率显著低于Hardy-Weinberg定理(&lt；0.02)的预期比率。INDI…的相对适合度当取2n=16=1时，2n=17的个体数为0.4。这一数字远低于杂合子的相对适合度，在戴森山杂交区(2n=18/20)的群体(Kawadoko)中为0.7。与染色体重排有关的染色体大小的差异可能解释了这一结果。我们分析了几个nigiricoxa种群和一些近缘种群的mtDNA编码的约1kb碱基的CO I基因序列。所获得的系统发育为：(千叶黑曲霉Mt.Kiyosumi Mt.Daisen 2n=22)(山口黑曲霉tokusen Falls，2n=22(Nigricoxa tokusen Falls，2n=20(Nigricoxa Mt.Senjo，2n=18(Nigricoxa Makiyaha Mt.Daisen 2n=20，Nigricoxa 2n=20 Makihara Mt.Daisen)。结果表明，在长谷地区一些形态未分化的黑线莲居群中，也可以检测到线粒体DNA水平上的形态分化。较少

To reveal the nature and formation process of chromosomal hybbrid zones in Nelima nigricoxa, we analyzed karyotypes, allozymes, and mtDNA for various populations of the species and the closely related congeners. A total of seven karyotypes were recongnized in Nelima nigricoxa : 2n=20 (Kyushu, Shikoku, and Chugoku district westward of the Asahi River), 2n=18a (West of Mt.Daisen, Tottori Pref.and Kinki district), 2n=18b (north of Okayama city), 2n=16 (Chugoku mountains eastward from the Asahi River), 2n=22a (Izu-Hakone), 2n=22b (Miura Peninsula), 2n=22c (Mt.Kiyosumi, Chiba Pref.). Of these, each of the three adjoining karyotype pairs (2n=20/18a, 2n=18a/16, and2n=16/18a) forms a hybrid zone with a width less than 1-3 km. In a population (Shimimu-dani) in a hybrid zone between 2n=16 and 18a in Sekigane-cho, Tottori Prefecture, the ratio of individuals with 2n=17 chromosomes was significantly lower than the expected ratio from the Hardy-Weinberg theorem (<0.02). The relative fitness of indi … More viduals with 2n=17 was 0.4 when taking 2n=16 equals 1. The figure was much lower than the relative fitness of heterozygotes, 0.7 obtained in a population (Kawadoko) in a hybrid zone (2n=18/20) in Mt.Daisen. Difference in the size of chromosomes that pertain to the chromosome rearrangement may explain this result.We analyzed sequences of about 1 kilobase pairs of CO I gene coded by the mtDNA for several population of N.nigiricoxa and some populations of the closest relatives. The phylogeny obtained was : (nigricoxa Mt.Kiyosumi, Chiba, 2n=22, genufusca Sapporo, 2n=22) (genufusca Tokusen Falls, Yamaguchi, 2n=22 (nigricoxa Tokusen Falls, Yamaguchi, 2n=20 (nigricoxa Mt.Senjo, 2n=18 (nigricoxa Makiyaha Mt.Daisen 2n=20, nigricoxa 2n=20 Makihara Mt.Daisen)))) and the bootstrap probability for each branch was 100% without exception. It was confirmed that grographic differentiation can be detected also in mtDNA level among some morphologically non-differentiatied populations of Nelima nigricoxa in the Chogoku district. Less