THE ECORI CENTROMERIC SATELLITE DNA OF THE SPARIDAE FAMILY (PISCES, PERCIFORMES) CONTAINS A SEQUENCE MOTIVE COMMON TO OTHER VERTEBRATE CENTROMERIC SATELLITE DNAS

By means of cloning, sequencing, and fluorescence in situ hybridizatio n, we have determined that the EcoRI satellite DNA family is conserved in the 10 sparid species analyzed here. Its conservation, its chromos omal location at the centromere of each chromosome, and its structural features could make this satellite DNA family an important structural and/or functional element of the centromeres of these species. Monome ric units of this satellite DNA have a consensus length of 187 bp. Its sequence is characterized by a high AT content and the presence of sh ort runs of consecutive AT base pairs. These monomeric EcoRI repeats a lso contain three to four copies, depending on the species, of a short sequence reflecting the repetitive duplication and subsequent diverge nce of an ancestral 9-bp sequence in this family. This sequence motive is conserved in some parts of the monomeric units of the different sp ecies studied at the same positions, and, precisely, surrounding the a rea in which the curvature of the monomeric molecule is greatest. The 9-bp sequence motive is similar to other direct-repeat sequences of th e centromeric satellite DNAs of other vertebrates, including those of amphibians and mammals.