Naslov
Tandemly repeated noncoding sequences: from junk DNA to notable genomic components

Autori
Plohl, Miroslav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
HDBMB 2004 : Book of Abstracts / Dumić, Jerka - Zagreb : Farmaceutsko-biokemijski fakultet Sveučilišta u Zagrebu, 2004, 35-35

Skup
Congress of the Croatian society of biochemistry and molecular biology, with international participation

Mjesto i datum
HOC Bjelolasica, Hrvatska, 30.09.2004. - 02.10.2004

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Domaća recenzija

Ključne riječi
satellite DNA; heterochromatin; evolution

Sažetak
Tandemly repeated sequences or satellite DNAs represent a major DNA component of heterochromatin, still the most mysterious and least understood genomic compartment. Once they were considered to accumulate without any function at all, solely due to low recombination rate in heterochromatic portions of chromosomes. However, recent results obtained by several groups favor their fundamental importance in function and evolution of eukaryotic genome. Evidence has been provided that long homogeneous domains of satellite repeats are the principal DNA component involved in centromeric function of animal and plant species, such as human, Drosophila and rice. Transcripts of satellite repeats are involved in formation of densely packed heterochromatin through RNAi mechanism. Paradoxically, satellite DNAs in centromeric heterochromatin change rapidly in evolution, and usually differ even among closely related organisms. That caused an adaptive coevolution of specific centromeric histone CENH3 and corresponding satellite DNA, what can in turn induce reproductive isolation between groups of organisms and trigger a speciation process. Study of satellite DNA dynamics in a model system of tenebrionid beetles showed that rapid changes in satellite profiles can be accomplished by differential amplification of sequences preexisting in the genomic pool, not necessarily due to rapid changes of their nucleotide sequences. Centromeric satellites of tenebrionid beetles form irregular patchwork of unexpectedly short, not longer than 100 kb, mutually interspersed arrays of each satellite. The distribution of arrays and structure of junctions is consistent with unequal crossing over as a mechanism of homogenization of satellite repeats. In contrast to the established opinion, the organizational structure of centromeric heterochromatin in tenebrionid beetles indicates that heterochromatin formation and centromeric function are not necessarily incompatible with dynamic recombinational events.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA