SIMPLE REPETITIVE DNA-SEQUENCES FROM PRIMATES - COMPILATION AND ANALYSIS

Simple repeats composed of tandemly repeated units 1-6 nucleotides (nt ) long have been extracted from a selected set of primate genomic DNA sequences. Of the 501 theoretically possible, different types of repea ts only 67 were present in the analyzed database in at least two diffe rent size ranges over 12 nt. They include all simple repeats known to be polymorphic in the primate genome. A list of moderately expanding a nd nonexpanding oligonucleotide patterns has also been included. Furth ermore, we have compiled statistical data with emphasis on the overall variability of the most abundant 67 types of repeats. We have demonst rated that the expandability of at least some simple repeats may be af fected by the overall base composition and by flanking sequences. In p articular, the occurrence of tandemly repeated CAG and GCC triplets in exons positively correlates with their G+C content. We also noted tha t in the vicinity of Alu sequences tetrameric repeats are more abundan t than in the total genomic DNA. This paper can be used as a comprehen sive guide in identification of the most abundant and potentially poly morphic simple repeats. It is also of broader significance as a step t oward understanding the contribution of flanking sequences and the ove rall sequence composition to variability of simple repeats.