Chromosome evolution in pseudoxyrhophiine snakes from Madagascar: a wide range of karyotypic variability. (16th June 2014)

• Record Type: Journal Article
• Authors: Mezzasalma, Marcello; Andreone, Franco; Branch, William R.; Glaw, Frank; Guarino, Fabio M.; Nagy, Zoltán T.; Odierna, Gaetano; Aprea, Gennaro
• Is Part Of: Biological journal of the Linnean Society. Volume 112:Number 3(2014:Jul.)
• Page Start: 450
• Page End: 460
• Publication Date: 2014-06-16
• Subjects: karyotype evolution -- Lamprophiidae -- Pseudoxyrhophiinae -- sex chromosome evolution; Biology -- Periodicals; Evolution (Biology) -- Periodicals; 570
• DOI: 10.1111/bij.12280
• Languages: English
• ISSNs: 0024-4066

Abstract

Abstract: In this first cytogenetic survey on the lamprophiid snake subfamily Pseudoxyrhophiinae, we studied the karyology of ten snake species belonging to seven genera from Madagascar ( Compsophis, Leioheterodon, Liophidium, Lycodryas, Madagascarophis, Phisalixella and Thamnosophis ) using standard and banding methods. Our results show a wide range of different karyotypes ranging from 2 n = 34 to 2 n = 46 elements (FN from 40 to 48), with nucleolus organizer regions (NORs) on one (plesiomorphic) or two (derived/apomorphic) microchromosome pairs, and W chromosome at early or advanced states of diversification from the Z chromosome. The observed W chromosome variations further support the most accepted hypothesis that W differentiation from the Z chromosome occurred by progressive steps. We also propose an evolutionary scenario for the observed high karyotype diversity in this group of snakes, suggesting that it is derived from a putative primitive pseudoxyrhophiine karyotype with 2 n = 46, similar to that of Leioheterodon geayi, via a series of centric fusions and inversions among macrochromosomes and translocations of micro- either to micro- or to macrochromosomes. This primitive Pseudoxyrhophiinae karyotype might have derived from a putative Lamprophiidae ancestor with 2 n = 48, by means of a translocation of a micro- to a macrochromosome. In turn, the karyotype of this lamprophiid common ancestor may have derived from the assumed primitive snake karyotype (2 n = 36 chromosomes, with 16 biarmed macro- and 20 microchromosomes) by a series of centric fissions and one inversion.