New record on karyological analysis and first study of NOR localization of parthenogenetic brahminy blind snake, Ramphotyphlops braminus (Squamata, Typhlopidae) in Thailand

Patawang, Isara; Tanomtong, Alongklod; Kaewmad, Puntivar; Chuaynkern, Yodchaiy; Duengkae, Prateep

doi:10.1007/s13237-015-0154-z

Cited by 10 publications

(13 citation statements)

References 3 publications

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“…The triploid karyotype of I. braminus (2n=3X=42) was first described by Wynn et al (1987) and subsequently confirmed by Ota et al (1991), Patawang et al (2016) and by our results (Fig. 1).…”

supporting

confidence: 88%

“…In the first place, I. braminus has conserved the plesiomorphic condition of NORs on a microchromosome pair, tentatively located on the 2nd microchromosome pair as suggested by a secondary constriction (see Wynn et al, 1987) and confirmed by Ag-NOR-banding (see Fig. 1 and Patawang et al, 2016. The primitive 2n=28 diploid ancestor of I. braminus may have derived from the primitive snake karyotype of 2n=36 (16 macro-and 20 microchromosomes) like that of M. arenarius by means of three micro-to microchromosome translocations plus a centric fusion involving macrochromosome pairs 5 and 6 (Fig.…”

mentioning

confidence: 75%

“…Moreover, all these species were investigated only by morphological staining methods, except Amerotyphlops brongersmianus and Indotyphlops braminus (Daudin, 1802(Daudin, [1802(Daudin, -1803) (Vanzolini, 1976;Patawang et al, 2016)) for which the Ag-NOR banding method was also applied (see Table 1 for details).…”

mentioning

confidence: 99%

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A karyological study of three typhlopid species with some inferences on chromosome evolution in blindsnakes (Scolecophidia)

Mezzasalma

Andreone

Glaw

et al. 2016

Zoologischer Anzeiger - A Journal of Comparative Zoology

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supporting

confidence: 88%

mentioning

confidence: 75%

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A karyological study of three typhlopid species with some inferences on chromosome evolution in blindsnakes (Scolecophidia)

Mezzasalma

Andreone

Glaw

et al. 2016

Zoologischer Anzeiger - A Journal of Comparative Zoology

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“…This was probably caused by copy number variation of the 18S-28S rRNA genes between triplet chromosomes. The morphological heteromorphism of chromosomes 1 and 7 found in this study was also observed in 10 individuals from Ryukyu Arc [Ota et al, 1991b], 5 individuals from Thailand [Patawang et al, 2016; chromosome 7 in the present study corresponds to chromosome 6 in the reference], 2 individuals from Mahé, the Seychelles, 4 individuals from Oahu, Hawaii, and 2 individuals from Coral Gables, Florida [Wynn et al, 1987]. Therefore, individuals that colonized the 5 regions may have come from the same ancestral parthenogenetic population.…”

Section: Discussionsupporting

confidence: 82%

“…Embryos of obligate parthenogenetic species develop without fertilization of eggs; thus, chromosome rearrangements tend to be easily fixed and accumulated in their karyotypes [Webb et al, 1978;White et al, 1982;Spence et al, 1998]. Heteromorphisms have been observed for the size of the nucleolus organizer region on chromosomes 8 (the largest triplet of microchromosomes) and in the morphologies of chromosomes 1 and 6 in I. braminus individuals collected in Thailand [Patawang et al, 2016].…”

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confidence: 99%

Karyotype Analysis of Four Blind Snake Species (Reptilia: Squamata: Scolecophidia) and Karyotypic Changes in Serpentes

Matsubara

Kumazawa

Ota

et al. 2019

Cytogenet Genome Res

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The suborder Serpentes is divided into 2 infraorders, Scolecophidia and Alethinophidia, which diverged at an early stage of snake diversification. In this study, we examined karyotypes of 4 scolecophidian species (Letheobia simonii, Xerotyphlops vermicularis, Indotyphlops braminus, and Myriopholis macrorhyncha) and performed FISH with 18S-28S rDNA as well as microchromosomal and Z chromosome-linked genes of Elaphe quadrivirgata (Alethinophidia) to investigate the karyotype evolution in the scolecophidian lineage. Diploid chromosome numbers of X. vermicularis and L. simonii were 30 (16 macrochromosomes and 14 microchromosomes) and 32 (16 macrochromosomes and 16 microchromosomes), respectively. The karyotype of a female M. macrorhyncha consisted of 15 macrochromosomes and 19 microchromosomes, including a heterochromatic microchromosome, indicating the presence of a heteromorphic chromosome pair. E. quadrivirgata Z-linked genes mapped to chromosome 4 of M. macrorhyncha, not to the heteromorphic pair. Therefore, M. macrorhyncha may have differentiated ZW sex chromosomes which are not homologous to those of E. quadrivirgata. One of the E. quadrivirgata microchromosomal genes mapped to the terminal region of chromosome 4q in X. vermicularis, suggesting that fusions between microchromosomes and macrochromosomes occurred in this species. rDNA was localized in different macrochromosomal pairs in the 2 diploid scolecophidian snakes examined here, whereas the gene location in a microchromosomal pair was conserved in 5 alethinophidian species examined. These results might imply the occurrence of chromosome fusions in the scolecophidian lineages. In I. braminus, a unique parthenogenetic snake with a triploid karyotype (21 macrochromosomes and 21 microchromosomes), morphological heteromorphisms were identified in chromosomes 1 and 7. Such heteromorphisms in 2 chromosomes were also observed in individuals from distant locations in the broad distribution range of this species, suggesting that the heteromorphisms were fixed in the genome at an early stage of its speciation.

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A widespread commensal loses its identity: suggested taxonomic revision for Indotyphlops braminus (Scolecophidia: Typhlopidae) based on molecular data

et al. 2022

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The widespread human commensal blindsnake species Indotyphlops braminus is currently the only known obligate parthenogenetic snake species. It is also known to be triploid. However, much of these data is from specimens collected outside India which is the native range of this species. Polyploidy and parthenogenesis are often associated with hybridization in amphibians and lizards. In this study, we generated nuclear and mitochondrial data from multiple Indotyphlops lineages from across peninsular India and investigated the possible hybrid origin of I. braminus. Species delimitation suggested three putative species, one of which was I. pammeces and the other two morphologically matched I. braminus. One of these was confined to the wet zone (high rainfall areas) while the other was largely distributed in the dry zone. There was wide discordance in the relationships between these lineages across markers and different tree building approaches suggesting past or ongoing geneflow. The statistical test for hybridization also implied geneflow across these three lineages. Furthermore, the dry zone I. braminus appears to be true I. braminus as the topotypic material falls within this clade. These results suggest that the widespread, commensal, and parthenogenetic Indotyphlops is a separate species from I. braminus, and further investigation is required to determine diagnostic morphological characters for a species description.

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New record on karyological analysis and first study of NOR localization of parthenogenetic brahminy blind snake, Ramphotyphlops braminus (Squamata, Typhlopidae) in Thailand

Cited by 10 publications

References 3 publications

A karyological study of three typhlopid species with some inferences on chromosome evolution in blindsnakes (Scolecophidia)

A karyological study of three typhlopid species with some inferences on chromosome evolution in blindsnakes (Scolecophidia)

Karyotype Analysis of Four Blind Snake Species (Reptilia: Squamata: Scolecophidia) and Karyotypic Changes in Serpentes

A widespread commensal loses its identity: suggested taxonomic revision for Indotyphlops braminus (Scolecophidia: Typhlopidae) based on molecular data

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