Sex Chromosomes and Meiosis in Spiders:A Review

Araujo, Douglas; Schneider, Marielle Cristina; Paula-Neto, Emygdio; Cella, Doralice Maria

doi:10.5772/31612

Cited by 33 publications

(35 citation statements)

References 35 publications

(90 reference statements)

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“…Araneomorphs represent lower diploid numbers than mygalomorphs, with haplogynes possessing diploid numbers between 7 (Ariadna lateralis Karsch, 1881, Segestriidae : Suzuki 1954) Up to now, 706 spider species have been cytogenetically investigated (Araujo et al 2013). More than 67.3% of spiders (Araujo et al 2012) have X 1 X 2 /¾X 1 X 1 X 2 X 2 type and most probably the X 1 X 2 0 system is ancestral as inferred from its presence in the most primitive spiders namely Mesothelae and some mygalomorph families (Atypidae and Dipluridae: Řezáč et al 2006).…”

Section: Discussionmentioning

confidence: 99%

Cytogenetic characterization of ten araneomorph spiders (Araneae): Karyotypes and meiotic features

Kumbıçak

2014

Biologia

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Karyotypes, sex chromosome systems and meiotic characteristics are reported for ten spider species belonging to the families Gnaphosidae, Philodromidae, Salticidae, Oxyopidae and Sicariidae by using standard Giemsa staining. The male diploid numbers (2n) and sex chromosome systems are as follows: Berinda hakani 2n = 22 (X1X2), Berinda ensigera 2n = 22 (X1X2), Trachyzelotes lyonneti 2n = 22 (X1X2), Trachyzelotes malkini 2n = 22 (X1X2), Zelotes caucasius 2n = 22 (X1X2) (Gnaphosidae); Thanatus pictus 2n = 28 (X1X2), Tibellus macellus 2n = 24 (X1X2) (Philodromidae); Neon reticulatus 2n = 21 (X0) (Salticidae); Peucetia virescens 2n = 28 (X1X2) (Oxyopidae) and Loxosceles rufescens 2n = 21 (X1X2Y) (Sicariidae). All species have monoarmed chromosomes with the exception of L. rufescens that has biarmed (metacentric and submetacentric) chromosomes. The obtained data are the first results for the genera Berinda, Trachyzelotes and Neon. Additionally, with the exception of L. rufescens, all species are being chromosomally analyzed for the first time.

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Section: Discussionmentioning

confidence: 99%

Cytogenetic characterization of ten araneomorph spiders (Araneae): Karyotypes and meiotic features

Kumbıçak

2014

Biologia

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“…Nevertheless, in groups phylogenetically related to Amblypygi, the occurrence of heteromorphic sex chromosomes has been reported. In Uropygi, the XY/XX and X0/XX sex chromosome systems were observed in species of the genus Thelyphonus, while in Araneae, a remarkable diversity of simple and multiple sex chromosome systems, including approximately 10 different types of system, was recorded in the 676 species studied (Araujo et al, 2012). Thus, the chromosomal investigation of a high diversity of Amblypygi species as well as other pedipalpids (Thelyphonida and Schizomida) offers an excellent opportunity to deepen our knowledge about chromosome diversity and to study the trends of sex chromosome evolution in the Tetrapulmonata arachnids.…”

Section: Discussionmentioning

confidence: 99%

Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders

Paula-Neto

Araujo²,

Carvalho³

et al. 2013

Genet. Mol. Res.

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ABSTRACT. We analyzed mitotic and meiotic cells of a Brazilian amblypygid, Heterophrynus longicornis, using conventional and molecular cytogenetic techniques (Giemsa staining, C-banding, Ag-NOR, and FISH with rDNA probe). This is the first study that focuses solely on amblypygid chromosomes; it was undertaken to add data on cytogenetic knowledge of this group and contribute to the understanding of chromosome evolution in the Arachnida. We found 2n = 66 for male and female individuals, monocentric chromosomes, and absence of morphologically differentiated sex chromosomes. C-banding showed heterochromatin in the pericentromeric region of most chromosomes. Mitotic and meiotic nuclei submitted to Chromosomal characteristics of a Brazilian whip spider silver impregnation and FISH revealed, respectively, Ag-NORs and ribosomal genes in the terminal region of two chromosome pairs. Most chromosome features that we observed in H. longicornis are shared with species of other arachnid orders; however, the absence of morphologically differentiated sex chromosomes in amblypygid contrasts with the remarkable variety of sex chromosome systems recorded for the Araneae. Consequently, we conclude that analysis of species of the Tetrapulmonata clade is useful for understanding the trends of sex chromosome evolution in this arachnid group.

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“…Indeed, an ultrastructural study of sex chromosome pairing is necessary to test this hypothesis. In addition to lycosids, the parallel pairing of X chromosomes has been described in male prophase I of most entelegynes analysed so far [for review see Araújo et al, 2012b]. In huntsman spiders (Sparassidae), sex chromosome pairing continues often until the end of the first meiotic division [Rowell, 1991].…”

Section: Discussionmentioning

confidence: 99%

“…different staining intensity), achiasmatic pairing and specific position in plates. Due to precocious condensation, the sex chromosomes of males usually display a higher staining intensity (positive heteropycnosis) during premeiotic interphase and prophase I and sometimes following meiotic phases [Araújo et al, 2012b]. The modes of sex chromosome pairing during male meiosis are diverse in spiders.…”

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confidence: 99%

Sex Chromosome Pairing and Extensive NOR Polymorphism in <b><i>Wadicosa fidelis</i></b> (Araneae: Lycosidae)

Forman

Nguyen

Hula

et al. 2013

Cytogenet Genome Res

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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.

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Sex Chromosomes and Meiosis in Spiders:A Review

Cited by 33 publications

References 35 publications

Cytogenetic characterization of ten araneomorph spiders (Araneae): Karyotypes and meiotic features

Cytogenetic characterization of ten araneomorph spiders (Araneae): Karyotypes and meiotic features

Chromosomal characteristics of a Brazilian whip spider (Amblypygi) and evolutionary relationships with other arachnid orders

Sex Chromosome Pairing and Extensive NOR Polymorphism in <b><i>Wadicosa fidelis</i></b> (Araneae: Lycosidae)

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