[Analysis of copies of the suffix-retroposon of Drosophila, produced using PCR on genomic DNA].

: Nineteen DNA clones, containing copies of the suffix element retroposon of the Drosophila genome and produced by a polymerase chain reaction (PCR), were sequenced. Insertions of the copies in both orientations into microsatellite sequences (CAACA)n/(TGTTG)n and (TTTGT)n/(CACAAA)n were revealed. It was found that, if the microsatellite sequence has both a decanucleotide GCGGCCCGGG (GC-box) and a colinear alternating sequence (A)5(T)4(A)3(T)2(A)1(t)n (AT-box), the insertion of the suffix occurs in only one orientation. It is suggested, that in such apparently heterochromatic sequences, suffix element copies and probably some other retroposons can be inserted a particular orientation by means of site-specific recombination. An approach to analysis of the molecular organization of such sequences is proposed.