PMID- 30558533 OWN - NLM STAT- MEDLINE DCOM- 20190319 LR - 20240405 IS - 1471-2164 (Electronic) IS - 1471-2164 (Linking) VI - 19 IP - 1 DP - 2018 Dec 17 TI - Chromosome map of the Siamese cobra: did partial synteny of sex chromosomes in the amniote represent "a hypothetical ancestral super-sex chromosome" or random distribution? PG - 939 LID - 10.1186/s12864-018-5293-6 [doi] LID - 939 AB - BACKGROUND: Unlike the chromosome constitution of most snakes (2n=36), the cobra karyotype shows a diploid chromosome number of 38 with a highly heterochromatic W chromosome and a large morphologically different chromosome 2. To investigate the process of sex chromosome differentiation and evolution between cobras, most snakes, and other amniotes, we constructed a chromosome map of the Siamese cobra (Naja kaouthia) with 43 bacterial artificial chromosomes (BACs) derived from the chicken and zebra finch libraries using the fluorescence in situ hybridization (FISH) technique, and compared it with those of the chicken, the zebra finch, and other amniotes. RESULTS: We produced a detailed chromosome map of the Siamese cobra genome, focusing on chromosome 2 and sex chromosomes. Synteny of the Siamese cobra chromosome 2 (NKA2) and NKAZ were highly conserved among snakes and other squamate reptiles, except for intrachromosomal rearrangements occurring in NKA2. Interestingly, twelve BACs that had partial homology with sex chromosomes of several amniotes were mapped on the heterochromatic NKAW as hybridization signals such as repeat sequences. Sequence analysis showed that most of these BACs contained high proportions of transposable elements. In addition, hybridization signals of telomeric repeat (TTAGGG)(n) and six microsatellite repeat motifs ((AAGG)(8), (AGAT)(8), (AAAC)(8), (ACAG)(8), (AATC)(8), and (AAAAT)(6)) were observed on NKAW, and most of these were also found on other amniote sex chromosomes. CONCLUSIONS: The frequent amplification of repeats might involve heterochromatinization and promote sex chromosome differentiation in the Siamese cobra W sex chromosome. Repeat sequences are also shared among amniote sex chromosomes, which supports the hypothesis of an ancestral super-sex chromosome with overlaps of partial syntenies. Alternatively, amplification of microsatellite repeat motifs could have occurred independently in each lineage, representing convergent sex chromosomal differentiation among amniote sex chromosomes. FAU - Singchat, Worapong AU - Singchat W AD - Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. FAU - O'Connor, Rebecca E AU - O'Connor RE AD - School of Biosciences, University of Kent, Canterbury, CT2 7NY, United Kingdom. FAU - Tawichasri, Panupong AU - Tawichasri P AD - Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. FAU - Suntronpong, Aorarat AU - Suntronpong A AD - Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. FAU - Sillapaprayoon, Siwapech AU - Sillapaprayoon S AD - Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. FAU - Suntrarachun, Sunutcha AU - Suntrarachun S AD - Department of Research and Development, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, 10330, Thailand. FAU - Muangmai, Narongrit AU - Muangmai N AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. AD - Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand. FAU - Baicharoen, Sudarath AU - Baicharoen S AD - Bureau of Conservation and Research, Zoological Park Organization under the Royal Patronage of His Majesty the King, Bangkok, Thailand. FAU - Peyachoknagul, Surin AU - Peyachoknagul S AD - Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, 65000, Thailand. FAU - Chanhome, Lawan AU - Chanhome L AD - Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, 10330, Thailand. FAU - Griffin, Darren AU - Griffin D AD - School of Biosciences, University of Kent, Canterbury, CT2 7NY, United Kingdom. FAU - Srikulnath, Kornsorn AU - Srikulnath K AUID- ORCID: 0000-0002-5985-7258 AD - Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand. kornsorn.s@ku.ac.th. AD - Animal Breeding and Genetics Consortium of Kasetsart University (ABG-KU), Bangkok, 10900, Thailand. kornsorn.s@ku.ac.th. AD - Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Kasetsart University, Bangkok, 10900, Thailand. kornsorn.s@ku.ac.th. AD - Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok, 10900, Thailand. kornsorn.s@ku.ac.th. LA - eng GR - RSA6180075/Thailand Research Fund/ GR - BB/K008161/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom GR - PHD60I0014/Thailand Research Fund/ GR - 2560096003012/the National Research Council of Thailand/ GR - BB/E010652/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom GR - PHD60I0082/Thailand Research Fund/ GR - 0513.10109/8384/the Fellowship of Capacity Building for Kasetsart University on Internationalization at Kasetsart University/ GR - GA/PhD/Sup/Year4/003/the Thailand Research Fund - Newton Fund Placement, Travel Grant for PhD Supervisors/ GR - -/the Center of Excellence on Agricultural Biotechnology, Science and Technology Postgraduate Education and Research Development Office, Office of Higher Education Commission, Ministry of Education/ GR - 80.60/Kasetsart University Research and Development Institute/ GR - -/the Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University/ GR - MSD60I0035/Thailand Research Fund/ PT - Journal Article DEP - 20181217 PL - England TA - BMC Genomics JT - BMC genomics JID - 100965258 RN - 0 (DNA Transposable Elements) SB - IM MH - Animals MH - Birds/genetics MH - Chickens/genetics MH - Chromosome Mapping MH - *Chromosomes MH - DNA Transposable Elements/genetics MH - Elapidae/*genetics MH - Female MH - In Situ Hybridization, Fluorescence MH - Karyotype MH - Lymphocytes/cytology/metabolism MH - Male MH - Metaphase MH - Microsatellite Repeats/genetics MH - *Sex Chromosomes MH - Synteny PMC - PMC6296137 OTO - NOTNLM OT - amniote OT - repeat sequences OT - sex chromosome OT - snake OT - synteny COIS- ETHICS APPROVAL AND CONSENT TO PARTICIPATE: Animal care and all experimental procedures were approved by the Animal Experiment Committee, Kasetsart University, Thailand (approval no. ACKU59-SCI-034 and ACKU61-SCI-024) and conducted in accordance with the Regulations on Animal Experiments at Kasetsart University. CONSENT FOR PUBLICATION: Not applicable. COMPETING INTERESTS: The authors declare that they have no competing interests. PUBLISHER'S NOTE: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. EDAT- 2018/12/19 06:00 MHDA- 2019/03/20 06:00 PMCR- 2018/12/17 CRDT- 2018/12/19 06:00 PHST- 2018/08/29 00:00 [received] PHST- 2018/11/21 00:00 [accepted] PHST- 2018/12/19 06:00 [entrez] PHST- 2018/12/19 06:00 [pubmed] PHST- 2019/03/20 06:00 [medline] PHST- 2018/12/17 00:00 [pmc-release] AID - 10.1186/s12864-018-5293-6 [pii] AID - 5293 [pii] AID - 10.1186/s12864-018-5293-6 [doi] PST - epublish SO - BMC Genomics. 2018 Dec 17;19(1):939. doi: 10.1186/s12864-018-5293-6.