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Karyotyping and cytogenetic mapping of A tlantic cod ( G adus morhua L innaeus, 1758)
Author(s) -
Ghigliotti L.,
Fevolden S.E.,
Cheng C.H. C.,
Babiak I.,
Dettai A.,
Pisano E.
Publication year - 2012
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/j.1365-2052.2012.02343.x
Subject(s) - biology , karyotype , genome , ploidy , genetics , gadus , chromosome , gene , atlantic cod , ribosomal rna , computational biology , evolutionary biology , fish <actinopterygii> , fishery
Summary The A tlantic cod ( G adus morhua ) is an important natural resource for northern societies and is now also considered to be a promising candidate for aquaculture. In recent years, much effort has been directed towards the development of genomic tools, and genome initiatives for A tlantic cod have been established. Despite the growing attention devoted to the Atlantic cod genomics, basic aspects of its genome structure and organization remain unknown. Thus, the present work aims to study cytogenetic features of the A tlantic cod as a contribution to the knowledge of this species' genome. The A tlantic cod displays a diploid number of 46 chromosomes, with a karyotypic formula 16 m/sm + 30 st/t. Conventional karyotyping was improved by chromosomal mapping of two classes of repetitive sequences. 18S rDNA clusters were assigned to pairs 2 and 4; small amounts of 18 S rDNA clusters were occasionally detected on pair 5. These findings could not be related to the geographical origin of the specimens, but were consistent with the variability of these repeated genes in fish in general. 5 S ribosomal gene clusters, apparently corresponding to a single 5 S rDNA class, were detected on twelve chromosomes (pairs 11, 12, 14, 17, 20 and 21). The present update of the existing but meagre information on the karyotype of A tlantic cod, plus the first physical mapping of repetitive genes in this species herein, opens the way for an integrated approach that combines genetic and physical mapping with the assembly of the genome of this commercially important species.