title: Comparative Chromosome Painting and NOR Distribution Suggest a Complex Hybrid Origin of Triploid Lepidodactylus lugubris (Gekkonidae).
abstract: Parthenogenesis, unisexuality and triploidy are interesting but poorly studied phenomena occurring in some reptile species. The mourning gecko (Lepidodactylus lugubris) represents a complex of diploid and triploid parthenogenetic mostly all-female populations (males occur quite rarely) widely distributed in coastal areas of the Indian and Pacific Oceans. Here, we study karyotypes of a male and two female L. lugubris (LLU) triploid individuals (3n = 66) using comparative painting with Gekko japonicus, Hemidactylus turcicus and H. platyurus chromosome specific probes to visualize the homologous regions and to reveal genus specific rearrangements. Also, we applied a 28S ribosomal DNA probe and Ag-staining to detect nucleolus organizer regions (NORs). Our results suggest that the karyotype of L. lugubris underwent a chromosome fission and a fusion after its divergence from a common ancestor of the Gekko-Hemidactylus group. The NORs were found to be located on one out of three homologs on each of LLU8, LLU15 and LLU18, thus further confirming a hybrid origin of triploid individuals. It seems that three different bisexual populations might have contributed to the origin of this triploid parthenogenetic population. We postulate that the heterozygosity in NOR localization is maintained in the triploid clone studied by the absence of recombination as described in whiptail lizards. The pattern of NOR localizations and homologous regions in males and females, as well as the absence of other detectable karyotypic differences, suggest that males arise spontaneously in all female populations and do not arise from independent hybridizations with different species.
authors.affiliation: Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia; Novosibirsk State University, Novosibirsk, Russia.
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Trifonov
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Paoletti
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy; Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima,Ancona, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Caputo Barucchi
authors.affiliation: Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia; Novosibirsk State University, Novosibirsk, Russia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kalinina
authors.affiliation: Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Patricia C M
authors.initials: PC
authors.lastname: O'Brien
authors.affiliation: Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Ferguson-Smith
authors.affiliation: Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Giovannotti
mesh_terms: D000818:Animals; D002678:Chimera / Q000235:genetics*; D005260:Female; D006801:Humans; D059785:Karyotype; D008116:Lizards / Q000235:genetics*; D008297:Male; D009697:Nucleolus Organizer Region / Q000235:genetics; D010312:Parthenogenesis; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D057885:Triploidy
chemical_list: D012339:RNA, Ribosomal, 28S