Molecular-cytogenetic analysis reveals sequence differences between the sex chromosomes of Oreochromis niloticus: evidence for an early stage of sex-chromosome differentiation

Publication Type:Journal Article
Year of Publication:2002
Authors:S. C. Harvey, Masabanda, J. , Carrasco, L. A. P. , Bromage, N. R. , Penman, D. J. , Griffin, D. K.
Journal:Cytogenetic and Genome Research
Accession Number:ISI:000178771400015
Keywords:cichlidae, DNA-sequence, Evolution, genetic sex determination, neo-y chromosome, OREOCHROMIS-NILOTICUS, sex-ratio, synaptonemal complex-analysis, tilapia

Sex determination in the Nile tilapia, Oreochromis niloticus, is primarily genetic, with XX females and XY males. A candidate sex-determining region in the terminal region of the largest chromosome pair has been identified by analysis of meiotic chromosomes. This region shows an inhibition of pairing and synapsis in the XY genotype, but not in XX or YY genotypes, suggesting that recombination is inhibited. Here we show that chromosome microdissection and subsequent amplification by degenerate oligonucleotide-primed PCR (DOP-PCR) can be used to produce in situ hybridization probes to this largest pair of O. niloticus chromosomes. Furthermore, analysis of the comparative hybridization of X and Y chromosome-derived probes to different genotypes provides the first demonstration that sequence differences exist between the sex chromosomes of O. niloticus. This provides further support for the theory that this chromosome pair is related to sex determination and further suggests that the sex chromosomes are at a very early stage of divergence.

Alternate Journal:Cytogenet Genome Res

Who's online

There are currently 0 users online.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith