BACKGROUND & AIMS:
:The cytogenetic characteristics of Eigenmannia aff. trilineata were analyzed by basic and molecular cytogenetics, applying fluorescent in situ hybridization, with 18S and 5S rDNA and U2 snRNA probes. The species revealed a kind of polymorphism associated to ZZ/Z0 type sex chromosomes, with 2n = 32 (8m+2sm+22a, NF = 42) in all males under analysis, whereas females evidenced 2n = 31 (8m+1sm+22a, NF = 40). C-banding showed constitutive heterochromatin restricted to the pericentromeric region of all chromosomes and single-nucleolus organized regions on pair 11. A site for rDNA 5S was synthetic with a cluster of rDNA 18S near the centromere on the long arm of only one homologue of pair 11. Other clusters for 5S rDNA were sited on pairs 7, 10, 12, 13, and 16. Further, 5S rDNA was co-located with U2 cluster in the pericentromeric region of pair 12. Joint analysis of DNA barcoding from cytochrome c oxidase subunit I (COI) sequences, generated from the karyotyped samples of E. aff. trilineata, and sequences of other Gymnotiforms recognized E. aff. trilineata as an Operational Taxonomic Unit. Results foreground the hypothesis that cytotypes are independent evolution units as cryptic species with a low morphological differentiation level, although with high genetic/karyotype differentiation rates.
背景与目标:
:本征曼氏体的细胞遗传学特征。用基本的和分子的细胞遗传学方法对三线虫进行了分析,并使用荧光原位杂交技术与18S和5S rDNA和U2 snRNA探针进行了杂交。该物种显示出一种与ZZ / Z0型性染色体相关的多态性,在分析中,所有雄性均为2n = 32(8m 2sm 22a,NF = 42),而雌性则显示为2n = 31(8m 1sm 22a,NF = 40)。 。 C谱带显示组成性异染色质仅限于对11上所有染色体的着丝粒区域和单核仁组织区域。一个rDNA 5S的位点是合成的,在着丝点附近长着丝粒的rDNA 18S簇只有一对同源。 11. 5S rDNA的其他簇位于对7、10、12、13和16。此外,5S rDNA与U2簇共位于对12的着丝粒区域中。联合分析来自细胞色素c氧化酶的DNA条形码亚型I(COI)序列,从aff。aff。的核型样本中产生。 trilineata,和其他裸Gym科动物的序列公认的大肠杆菌。 trilineata作为业务分类单位。结果提出了这样的假说,即细胞类型是作为隐性物种的独立进化单位,具有较低的形态分化水平,尽管具有较高的遗传/核型分化率。