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Chromosome diversity in Buthidae and Chactidae scorpions from Brazilian fauna: Diploid number and distribution of repetitive DNA sequences

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Author(s):
Lima, Juliana Figueiredo ; Carvalho, Leonardo Sousa ; Carvalho, Marcos Andre ; Schneider, Marielle Cristina
Total Authors: 4
Document type: Journal article
Source: GENETICS AND MOLECULAR BIOLOGY; v. 46, n. 2, p. 11-pg., 2023-01-01.
Abstract

In this work, we analyzed cytogenetically eight Chactidae and Buthidae, including the localization of repetitive DNA sequences. The chactids possess monocentric chromosomes and the highest diploid numbers (2n=50 in Brotheas amazonicus, 2n=36 in Chactopsis amazonica, 2n=30 in Neochactas sp.) when compared with buthids (2n=10 in Tityus bahiensis, 2n=14 in Tityus apiacas and Tityus metuendus, 2n=18 in Tityus aba, 2n=26 in Ischnotelson peruassu). The localization of rDNA genes and (TTAGG)n sequences exhibited a conserved pattern of two terminal/subterminal ribosomal cistrons and terminal telomere signals. However, the comparison between the data of C-banding, DAPI after FISH and Cot-DNA fraction indicated a variable quantity and distribution of these regions, as follow: (i) positive heterochromatin and Cot-DNA signals (B. amazonicus and I. peruassu), (ii) small blocks of heterochromatin with large Cot-DNA signals (T. metuendus), (iii) positive heterochromatic regions and absence of Cot-DNA signals (T. aba and T. apiacas), and (iv) negative heterochromatin and Cot-DNA signals (T. bahiensis). Therefore, our results revealed that there still is not a clear relation between quantity of heterochromatin and presence of monocentric or holocentric chromosomes and occurrence of chromosomal rearrangements, indicating that repetitive regions in scorpions must be analyzed using different cytogenetic approaches. (AU)

FAPESP's process: 11/21643-1 - Meiosis in scorpions (Arachnida): model to understand the evolution in species with achiasmate chromosomes
Grantee:Marielle Cristina Schneider
Support Opportunities: Research Grants - Young Investigators Grants