Characterization of several LINE-1 elements in Microtus kirgisorum

Several LINE-1s have been isolated and characterized from genomic DNA of the vole, Microtus kirgisorum. Blot hybridization revealed specific restriction patterns of L 1 elements in vole genomes. Rehybridization of the genomic blot with a cloned 5'-end fragment revealed two major bands indicating the presence of two different L1 subfamilies. The copy numbers are estimated for different parts of M. kirgisorum L1 elements. Data also demonstrate that most vole L1 elements are truncated at the 5'-end; however, in contrast to mouse, the ORF1 copy number is higher in vole. A difference between the substitution rates of the ORF1 5'-region (approximately 330 nucleotides) and the rest of the L1 coding regions is revealed.