Homologous and differentiated ZZ/ZW sex chromosomes (or derived multiple neo-sex chromosomes) were often described in caenophidian snakes, but sex chromosomes were unknown until recently in non-caenophidian snakes. Previous studies revealed that two species of boas (Boa imperator, B. constrictor) and one species of python (Python bivittatus) independently evolved XX/XY sex chromosomes. In addition, heteromorphic ZZ/ZW sex chromosomes were recently revealed in the Madagascar boa (Acrantophis sp. cf. dumerili) and putatively also in the blind snake Myriopholis macrorhyncha. Since the evolution of sex chromosomes in non-caenophidian snakes seems to be more complex than previously thought, we examined ten species of pythons and boas representing the families Boidae, Calabariidae, Candoiidae, Charinidae, Pythonidae, and Sanziniidae by conventional and molecular cytogenetic methods, aiming to reveal their sex chromosomes. Our results show that all examined species do not possess sex-specific differences in their genomes detectable by the applied cytogenetic methods, indicating the presence of poorly differentiated sex chromosomes or even the absence of sex chromosomes. Interestingly, fluorescence in situ hybridization with telomeric repeats revealed extensive distribution of interstitial telomeric repeats in eight species, which are likely a consequence of intra-chromosomal rearrangements.

Department of Ecology Faculty of Science Charles University 12844 Prague Czech Republic

Department of Zoology Faculty of Science Charles University 12844 Prague Czech Republic

Institute of Animal Physiology and Genetics Czech Academy of Sciences 27721 Liběchov Czech Republic

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Sex Chromosome Turnovers and Stability in Snakes

Cytogenetic Analysis of Seven Species of Gekkonid and Phyllodactylid Geckos

ZZ/ZW Sex Chromosomes in the Madagascar Girdled Lizard, Zonosaurus madagascariensis (Squamata: Gerrhosauridae)

Cytogenetic Analysis of the Members of the Snake Genera Cylindrophis, Eryx, Python, and Tropidophis

Sex chromosome evolution among amniotes: is the origin of sex chromosomes non-random?

Cytogenetic Evidence for Sex Chromosomes and Karyotype Evolution in Anguimorphan Lizards

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