engleski

Highly repeated non-coding DNA in Tribolium castaneum (Coleoptera) genome

Non-coding DNAs are genomic sequences that do not encode for functional molecules. Satellite DNAs are non-coding DNA sequences repeated in tandem that compose significant portions of every eukaryotic genome. Many reports support involvement of satellite DNAs in complex structural and functional features of centromeric regions, but still, little is known about general functional features of these sequences. The genus Tribolium consists of species, some of them distantly related, which provide an excellent basis for evolutionary studies of satellite sequences. An extensive work on satellite DNAs in Tribolium species shows presence of high amounts (up to 40%) of different, centromeric species-specific satellite DNAs which share common structural features. Recently, Tribolium castaneum became the first coleopteran species with sequenced genome and emerged as a powerful insect model organism, especially in comparative analysis with Drosophila melanogaster. However, satellite repeats are underrepresented in assembled outputs of genome projects and high-resolution view of their composition and organization remains obscure. Results based on our in silico and experimental analysis of four different, highly abundant satellite DNAs, extracted from T. castaneum genome database, will be presented. Analysis of structure, organization, abundance and evolution in the genome, as well as a comparative studies of these satellite families show monomer length range between 166 and 370 pb, abundance from 0, 1 to 17 %, different monomer diversity among families, organization in form of randomly mixed monomer variants, higher-order-repeats (HOR) of subfamilies or arrays of specific subfamilies and peri(centromeric) localization or dispersed pattern. Understanding different features of this sequence type in the sequenced Tribolium castaneum genome will help to gain a more comprehensive view of their possible role(s) in genome architecture and function.

satellite DNA ; Tribolium castaneum

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