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キーワード:
Animals
Arvicolinae/*genetics
Base Sequence
Blotting, Northern
Cell Line
Chromosome Mapping
*Heterochromatin
Mammals
Molecular Sequence Data
*Retroelements
Sequence Homology, Nucleic Acid
要旨:
The heterochromatin of Microtus agrestis contains two retroposons, one L1 and one non-L1, which were cloned and analyzed with respect to their structure and genomic organization. These sequences have accumulated in the heterochromatin and exhibit a complex interspersed organization of relatively recent origin. In contrast, the pericentromeric heterochromatin is composed of simple, repetitive, tandemly organized elements. From the underlying sequences, the dinucleotide frequencies, the sequence organization, and its transcriptional activity, the heterochromatin of M. agrestis strongly resembles the beta-heterochromatin first described by Heitz and well characterized in Drosophila. This is evidence that this class of heterochromatin, presumably with its own distinct physiological and functional role, is indeed also present in the mammalian genome.