DISTRIBUTION OF THE NLRCTH1 NON-LTR RETRO TRANSPOSON IS RESTRICTED TOTHE GENUS CHIRONOMUS

Distribution of the NLRCthl non-LTR retrotransposon from Chironomus th ummi was studied in 23 species from four genera from the family Chirom onidae by in situ hybridization. The mobile element was detected in 18 species, all belonging to the genus Chironomus. In this genus, hybrid ization was detected in 10 to 150 sites per genome. Genomic DNA from e ight species was studied by Southern blot hybridization. NLRCthl-homol ogous non-LTR retrotransposons from the genus Chironomus were shown to form a family that includes three types of elements exhibiting homolo gous regions within ORF2.