Sex chromosome pairing and extensive NOR polymorphism in Wadicosa fidelis (Araneae: Lycosidae)

0392488 - BC 2014 RIV CH eng J - Journal Article
Forman, M. - Nguyen, Petr - Hůla, V. - Král, J.
Sex chromosome pairing and extensive NOR polymorphism in Wadicosa fidelis (Araneae: Lycosidae).
Cytogenetic and Genome Research. Roč. 141, č. 1 (2013), s. 43-49. ISSN 1424-8581. E-ISSN 1424-859X
Grant - others:AV ČR(CZ) IAA601110808; MSM ČR(CZ) LA10036; MSM ČR(CZ) SVV 2013-267205; GA JU(CZ) 137/2010/P; GA JU(CZ) 059/2010/P
Institutional support: RVO:60077344
Keywords : arachnid * ectopic recombination * facultative
Subject RIV: EB - Genetics ; Molecular Biology
Impact factor: 1.905, year: 2013

In terms of cytogenetics, entelegyne araneomorphs are the best studied clade of spiders. The typical karyotype of entelegyne males consists of acrocentric chromosomes, including 2 non-homologous X chromosomes. The present study is focused on the karyotype, nucleolus organising regions (NORs) and sex chromosome behaviour during meiosis of the entelegyne Wadicosa fidelis (Lycosidae). Preparations stained by Giemsa were used to study karyotype and meiosis. NORs were visualised by silver staining and fluorescence in situ hybridisation with 18S rDNA probe. The male karyotype consists of 28 acrocentric elements, including 2 X chromosomes. In contrast to the majority of other spiders, the male sex chromosomes pair during the major part of meiosis. Following an initial period of parallel pairing, the attachment of male sex chromosomes is restricted to centromeric areas and continues until metaphase II. Our study revealed an enormous number of NORs in the population from Galilee and indicates a considerable variability of NOR numbers in this population. The distal regions of 9 or 10 autosomal pairs contain NORs. The obtained data indicate the rapid spread of NORs in the karyotype of W. fidelis, which was presumably caused by ectopic recombinations and subsequent hybridisations of individuals with different NOR genotypes that produced heterozygotes.
Permanent Link: http://hdl.handle.net/11104/0223786