Abstract
Scorpions of the genus Tityus show holokinetic chromosomes, achiasmatic male meiosis and an absence of heteromorphic sex chromosomes, like all Buthidae. In this work, we analysed the meiotic behaviour and chromosome rearrangements of a population of the scorpion Tityus confluens, characterising the cytotypes of males, females and embryos with different cytogenetic techniques. This revealed that all the females were structural homozygotes, while all the males were structural heterozygotes for different chromosome rearrangements. Four different cytotypes were described in males, which differed in chromosome number (2n = 5 and 2n = 6) and meiotic multivalent configurations (chains of four, five and six chromosomes). Based on a detailed mitotic and meiotic analysis, we propose a sequence of chromosome rearrangements that could give rise to each cytotype and in which fusions have played a major role. Based on the comparison of males, females and a brood of embryos, we also propose that the presence of multivalents in males and homologous pairs in females could be associated with the presence of cryptic sex chromosomes, with the male being the heterogametic sex. We propose that the ancestral karyotype of this species could have had homomorphic XY/XX (male/female) sex chromosomes and a fusion could have occurred between the Y chromosome and an autosome.
Highlights
Buthidae is the most diverse family of scorpions of the Parvorder Buthida, which includes the poorly diversified families Chaerilidae and Pseudochactidae, and is clearly separate fromPLOS ONE | DOI:10.1371/journal.pone.0164427 October 26, 2016Sex-Linked Chromosome Heterozygosity in Males of Tityus confluens
Based on a detailed mitotic and meiotic analysis by Giemsa staining, C-banding, silver staining and Fluorescence in situ hybridisation (FISH) with 28S rDNA and (TTAGG)n telomeric probes, we propose a sequence of chromosome rearrangements that could give rise to each cytotype
Based on the comparison of males, females and embryos, we propose that the presence of multivalents in males and homologous pairs in females could be associated with the presence of cryptic sex chromosomes
Summary
Buthidae is the most diverse family of scorpions of the Parvorder Buthida, which includes the poorly diversified families Chaerilidae and Pseudochactidae, and is clearly separate from. Tityus is the most cytogenetically studied genus of Buthidae, with 18 species analysed It presents a wide interspecific variation in chromosome number, from 2n = 5 to 2n = 20, and most of the species present different multivalent associations at meiosis I [7, 8, 24, 25]. Multivalents in scorpions are often theoretically discussed, without aiming to reconstruct the type and probable order of chromosome rearrangements involved in their origin Another question that arises when studying polymorphic populations is whether the same chromosome rearrangements are present in males and females and how these are being transmitted across generations. Based on the comparison of males, females and embryos, we propose that the presence of multivalents in males and homologous pairs in females could be associated with the presence of cryptic sex chromosomes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
