Nucleotide sequence, genomic organization and evolution of a major repetitive DNA family in tilapia (Oreochromis mossambicus/hornorum).
A highly repetitive DNA sequence from tilapia (Oreochromis mossambicus/hornorum) has been cloned and sequenced. It is a tandemly arrayed sequence of 237 bp and constitutes 7% of the fish genome. The copy number of the repeat is approximately 3 x 10(5) per haploid genome. DNA sequence analysis of 7 cloned repeats revealed a high degree of conservation of the monomeric unit. Within the monomeric unit, a 9 bp AT rich motif is regularly spaced approximately 30 bp apart and may represent the progenitor of the amplified sequence. One cloned repeat, Ti-14, contained a 30 bp deletion at a position flanked by a 7 bp direct repeat. The Ti-14 sequence appears to have been amplified independently of the major 237 bp tandem array. A higher-order repeat unit, defined by longer-range periodicities revealed by restriction endonuclease digestion, is further imposed on the tandem array.
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
J M
JM
Wright
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004276:DNA, Satellite / Q000097:blood / Q000235:genetics*; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping
D004276:DNA, Satellite