Sainz J, Azorín F, Cornudella L
Unidad de Química Macromolecular del CSIC, Universitat Politécnica de Catalunya, Barcelona, Spain.
Gene. 1989 Aug 1;80(1):57-64. doi: 10.1016/0378-1119(89)90250-3.
A highly reiterated sequence in the sperm DNA of the echinoderm Holothuria tubulosa has been isolated by digestion with EcoRI, and cloned in the phagemid Bluescript. The monomeric unit has a repeat length of 391 bp and is arranged in tandem. The uncloned genomic monomer as well as two independent cloned fragments have been sequenced. The repeated element constitutes about 1.8% of total Holothuria DNA which corresponds to a repetition frequency of about 1.4 x 10(5) copies per haploid complement. The repetitive sequence has a high A + T content (66.8%) characterized by scattered tracts of A and T residues with no apparent internal sub-repeats, although several inverted and direct repeats are present. Heterogeneity between monomers derived from individual clones is low, whereas sequence similarity to known repetitive elements appears to be negligible.
