XX/XY sex chromosome system and chromosome markers in the snake eel Ophisurus serpens (Anguilliformes: Ophichtidae)

ABSTRACT

We report evidence of an XX/XY sex chromosome system in the snake eel Ophisurus serpens (Anguilliformes: Ophichthidae). We characterized the male and female karyotypes by C-, replication- and HaeIII-bandings. The 45S and 5S ribosomal gene families were located using dual fluorescence in situ hybridization, which showed that the 5S rDNA sites were present on the X chromosome, beside an autosome pair. FISH with a telomeric peptide nucleic acid probe enabled recognition of Interstitial Telomeric Sequences (ITSs), likely remnants of chromosomal rearrangements, in five chromosome pairs, including the rDNA-bearing ones. Possible mechanisms of the origin of sex chromosomes in this species are discussed, considering the presence of a sex-linked marker and ITSs.

SUBJECT EDITOR:

• Audrey J. Geffen

KEYWORDS:

• Anguilliformes
• karyotype evolution
• Ophisurus serpens
• rDNA
• telomeric sequences
• XX/XY sex chromosome system

Acknowledgements

We thank Professor U. Laudani, Professor V. Scali and PhD A. Cau for helpful suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Susanna Salvadori http://orcid.org/0000-0001-7664-6084

Elisabetta Coluccia http://orcid.org/0000-0003-4412-8033

Additional information

Funding

This work was supported by Fondazione Banco di Sardegna [Grant Number PRID 2015-17].