Here, a new satellite-DNA family is isolated and characterized from wedge sole, Dicologoglossa cuneata Moreau, 1881 (Pleuronectiformes), a fish having a small genome. This satellite-DNA family of sequences was isolated by conventional cloning after digestion of genomic DNA with the DraI restriction enzyme. Repeat units are 171 bp in length with a high AT content (63%). Several runs of consecutive adenines and thymines were found, and concomitantly computer analyses revealed that these regions are prone to acquire stable sequence-directed curvature. Especially remarkable is that the DraI sequences are composed almost entirely of the repetition of up to fourteen 9-bp motifs (T/C)GTC(A/C)AAAA similar to other vertebrate centromeric satellite-DNA sequences. In fact, we demonstrate the origin of this satellite through duplication of this motif plus the addition of a stretch of cytosines. The centromeric location and the presence in this satellite-DNA sequence of not only different vertebrate motifs (CENP-B box, pJalpha) but also others such as the CDEIII motif of Saccharomyces cerevisiae reveal a possible role in centromere function. All these characteristics provide important information on the origin, function, and the evolution of the centromeric satellite DNAs in wedge sole.
Copyright 2008 S. Karger AG, Basel.