首次对蟹蛛科（蜘蛛目）进行染色体分析揭示了性染色体系统 XXXX、B 染色体和着丝粒融合的多态性。

First chromosomal analysis in Deinopidae (Araneae) reveals Sex Chromosome System XXXX, B chromosomes and polymorphism for centric fusion.

机构信息

Laboratório de Citotaxonomia e Evolução Cromossômica Animal, Universidade Federal de Mato Grosso do Sul, UFMS, Instituto de Biociências, Cidade Universitária, Caixa Postal 549, CEP 79070-900, Campo Grande, Brazil.

出版信息

Zoology (Jena). 2021 Jun;146:125906. doi: 10.1016/j.zool.2021.125906. Epub 2021 Feb 12.

DOI:10.1016/j.zool.2021.125906

PMID:33636668

Abstract

Here we present the first cytogentic study concerning Deinopidae and their controversial phylogenetic position. This study karyologically analyzed one population of Deinopis biaculeata Simon, 1906 and five populations of Deinopis plurituberculata Mello-Leitão, 1925. The majority of specimens of D. plurituberculata exhibited 2n♂ = 40 and 2n♀ = 44 telocentric chromosomes (however some of them showed B chromosomes, belongs to Aquidauana and Botucatu population). The Deinopis biaculeata and D. plurituberculata meiosis of males showed 18 autosomal bivalents + XXXX, n = 22 and n = 18, a rare sex chromosome system (SCS) in spiders. Some individuals of D. plurituberculata from the Campo Grande population exhibited 2n♂ = 39 and 2n♀ = 43, with a metacentric chromosome (heterozygotes for centric fusion). The D. plurituberculata males with the rearrangement exhibit diplotenes with 16 autosomal bivalents + 1 autosomal trivalent + XXXX and metaphases II with n = 22 (18 telocentric autosomes + XXXX), n = 21 (16 telocentric autosomes + a metacentric autosome + XXXX), n = 18 (18 telocentric autosomes) and n = 17 (16 telocentric autosomes + a metacentric autosome). The Ag-NORs (silver impregnation) are terminally located in a pair, coinciding with secondary constriction, which is the most common configuration for Araneae. The relatively high diploid number in Deinopis corroborates phylogenies that place it in a basal position among Entelegynes, in the UDOH grade (Uloboridae, Deinopidae, Oecobiidae and Hersiliidae). Centric fusion in only one population of D. plurituberculata suggests low dispersion capacity of this species and an absence of homozygotes for fusion suggests their low viability or a need to increase the population sampling of D. plurituberculata exhibiting the rearrangement. B chromosomes were detected in D. plurituberculata, with interpopulacional, intrapopulacional and intraindividual numerical variation, with cells presenting 0 - 3 and 0 - 6 B chromosomes in populations of Aquidauana and Botucatu, respectively.

摘要

我们在此介绍了有关 Deinopidae 的首个细胞遗传学研究及其有争议的系统发育地位。本研究对 1 个 Deinopis biaculeata Simon, 1906 种群和 5 个 Deinopis plurituberculata Mello-Leitão, 1925 种群进行了核型分析。大多数 Deinopis plurituberculata 标本具有 2n♂ = 40 和 2n♀ = 44 着丝粒染色体（然而，其中一些具有 B 染色体，属于 Aquidauana 和 Botucatu 种群）。Deinopis biaculeata 和 D. plurituberculata 的雄性减数分裂显示 18 个常染色体二价体+XXXX，n = 22 和 n = 18，这是蜘蛛中罕见的性染色体系统（SCS）。来自 Campo Grande 种群的一些 D. plurituberculata 个体具有 2n♂ = 39 和 2n♀ = 43，具有着丝粒染色体（着丝粒融合的杂合体）。具有重排的 D. plurituberculata 雄性个体显示出具有 16 个常染色体二价体+1 个常染色体三价体+XXXX的二价体和具有 n = 22（18 个端着丝粒常染色体+XXXX）、n = 21（16 个端着丝粒常染色体+一个着丝粒常染色体+XXXX）、n = 18（18 个端着丝粒常染色体）和 n = 17（16 个端着丝粒常染色体+一个着丝粒常染色体）的中期 II。Ag-NORs（银染）位于一对中，与次级缢痕重合，这是蛛形纲最常见的构型。Deinopis 中的相对高的二倍体数支持将其置于 Entelegynes 中的基础位置的系统发育，在 UDOH 等级（Uloboridae、Deinopidae、Oecobiidae 和 Hersiliidae）中。在 D. plurituberculata 的仅一个种群中发现的着丝粒融合表明该物种的分散能力较低，融合的纯合子缺失表明其生存能力较低或需要增加表现出重排的 D. plurituberculata 的种群采样。在 D. plurituberculata 中检测到 B 染色体，具有种群间、种群内和个体内的数值变异，在 Aquidauana 和 Botucatu 种群中，细胞分别具有 0-3 和 0-6 个 B 染色体。