engleski

Short interspersion pattern of satellite DNA arrays in heterochromatin of tenebrionid beetles (Coleoptera)

Satellite DNAs in tenebrionid beetles are uniformly distributed in pericentromeric heterochromatin of all chromosomes. The length and organization of satellite DNA arrays has been assessed by multicolor fluorescent in situ hybridization on metaphase chromosomes, extended chromosomes and on DNA fibers. In Tenebrio molitor, arrays of a single highly abundant satellite on average 45 kilobases (kb) long are interrupted by short segments of other sequences. Two Tribolium madens satellite DNAs form highly interspersed pattern with arrays of a single satellite ranging from only few to maximally 70 kb. Gaps on DNA fibers that did not hybridize with either of the satellites are infrequent and short, indicating small contribution of non-satellite sequences in the heterochromatin. Similar can be concluded for distribution of two satellites in Tribolium brevicornis. No chromosome specificity in sequence organization of satellite DNAs was observed, and the same pattern spans the whole centromeric heterochromatin, probably including a region of functional centromere, as well. The patchwork of satellite arrays along the pericentromeric heterochromatin of all chromosomes distinguishes the long-range organization in tenebrionid insects from organization described in other species, where satellite DNAs build long uninterrupted arrays several hundreds kb in length.

heterochromatin ; satellite DNA ; fluorescent in itu hybridization

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