Král Jiří, Ávila Herrera Ivalú M, Šťáhlavský František, Sadílek David, Pavelka Jaroslav, Chatzaki Maria, Huber Bernhard A
Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague 2, Czech Republic Charles University Prague Czech Republic.
Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague 2, Czech Republic Charles University Prague 2 Czech Republic.
Comp Cytogenet. 2022 Nov 2;16(4):185-209. doi: 10.3897/CompCytogen.v16i4.85059. eCollection 2022.
Haplogyne araneomorphs are a diverse spider clade. Their karyotypes are usually predominated by biarmed (i.e., metacentric and submetacentric) chromosomes and have a specific sex chromosome system, XXY. These features are probably ancestral for haplogynes. Nucleolus organizer regions (NORs) spread frequently from autosomes to sex chromosomes in these spiders. This study focuses on pholcids (Pholcidae), a highly diverse haplogyne family. Despite considerable recent progress in pholcid cytogenetics, knowledge on many clades remains insufficient including the most species-rich pholcid genus, Walckenaer, 1805. To characterize the karyotype differentiation of in Europe, we compared karyotypes, sex chromosomes, NORs, and male meiosis of seven species [ Spassky, 1932; Senglet, 1971; Wunderlich, 1995; Wunderlich, 1992; (Fuesslin, 1775); (Schrank, 1781); Wunderlich, 1995] representing the dominant species groups in this region. The species studied show several features ancestral for , namely the 2n♂ = 25, the XXY system, and a karyotype predominated by biarmed chromosomes. Most taxa have a large acrocentric NOR-bearing pair, which evolved from a biarmed pair by a pericentric inversion. In some lineages, the acrocentric pair reverted to biarmed. Closely related species often differ in the morphology of some chromosome pairs, probably resulting from pericentric inversions and/or translocations. Such rearrangements have been implicated in the formation of reproductive barriers. While the X and Y chromosomes retain their ancestral metacentric morphology, the X chromosome shows a derived (acrocentric or subtelocentric) morphology. Pairing of this element is usually modified during male meiosis. NOR patterns are very diverse. The ancestral karyotype of contained five or six terminal NORs including three X chromosome-linked loci. The number of NORs has been frequently reduced during evolution. In the Macaronesian clade, there is only a single NOR-bearing pair. Sex chromosome-linked NORs are lost in Madeiran species and in . Our study revealed two cytotypes in the synanthropic species (Madeiran and Czech), which differ by their NOR pattern and chromosome morphology. In the Czech cytotype, the large acrocentric pair was transformed into a biarmed pair by pericentric inversion.
简腹蛛类蜘蛛是一个多样化的蜘蛛类群。它们的核型通常以双臂染色体（即中着丝粒染色体和亚中着丝粒染色体）为主，并且具有特定的性染色体系统XXY。这些特征可能是简腹蛛类的祖先特征。在这些蜘蛛中，核仁组织区（NORs）经常从常染色体扩散到性染色体。本研究聚焦于幽灵蛛科（Pholcidae），这是一个高度多样化的简腹蛛类家族。尽管幽灵蛛细胞遗传学最近取得了相当大的进展，但包括最具物种丰富度的幽灵蛛属（Walckenaer，1805年）在内的许多类群的知识仍然不足。为了描述欧洲[Spassky，1932年；Senglet，1971年；Wunderlich，1995年；Wunderlich，1992年；（Fuesslin，1775年）；（Schrank，1781年）；Wunderlich，1995年]七个代表该地区优势物种组的物种的核型分化，我们比较了它们的核型、性染色体、NORs和雄性减数分裂。所研究的物种显示出一些该类群的祖先特征，即2n♂ = 25、XXY系统以及以双臂染色体为主的核型。大多数分类单元有一对大型近端着丝粒且带有NOR的染色体，它是由一对双臂染色体通过着丝粒倒位进化而来的。在一些谱系中，近端着丝粒对又变回了双臂染色体。亲缘关系相近的物种在某些染色体对的形态上常常不同，这可能是由着丝粒倒位和/或易位导致的。这种重排与生殖隔离的形成有关。虽然X和Y染色体保留了它们祖先的中着丝粒形态，但X染色体呈现出一种衍生的（近端着丝粒或亚端着丝粒）形态。在雄性减数分裂过程中，这个染色体的配对通常会发生改变。NOR模式非常多样。该类群的祖先核型包含五个或六个末端NORs，其中包括三个与X染色体连锁的位点。在进化过程中，NORs的数量经常减少。在马卡罗尼西亚类群中，只有一对带有NOR的染色体。在马德拉群岛的物种和[此处原文缺失具体物种名]中，与性染色体连锁的NORs丢失了。我们的研究揭示了共栖物种[此处原文缺失具体物种名]（马德拉群岛和捷克的）中的两种细胞型，它们在NOR模式和染色体形态上有所不同。在捷克细胞型中，大型近端着丝粒对通过着丝粒倒位转变为双臂对。
