Investigating the evolution of satellite DNAs in holocentric chromosomes of pest species

Abstract

The satellite DNAs (satDNA) are repetitive sequences organized in tandem, forming in general large arrays and comprising large portion of eukaryote genomes. They are peculiarly enriched in heterochromatic regions, mainly in centromeres. These sequences play role in chromosomal structure and recently functionality for them has been described. The genomic and chromosomal organization and the evolutionary patterns for this DNA class are well known in species with monocentric chromosomes (located centromeres). The theories about satDNA evolution, like the library hypothesis and concerted evolution were postulated in monocentric chromosomes. On the other hand, among species with holocentric chromosomes (diffuse centromere) almost no knowledge about molecular evolution of this DNA class was obtained. This group is interesting for analysis due to the disperse organization for heterochromatin that could influence the evolution of satDNAs. The study of satDNA in species with holocentric chromosomes will allow the test of hypothesis about satDNA evolution and their impact in the karyotypic organization and variability. Moreover, it will be possible the generation of broader theories about satDNA biology. In this way, in this proposal we intend to advance in the knowledge about structure and evolution of satDNAs, using as experimental models pest insects (Hemiptera and Lepidoptera) with holocentric chromosomes. Finally, we will contribute with the genome assembling of pest species that could have applicability in the future. For this aim we will use an integrative analysis combining cytogenetics, genomics (next generation sequencing) and bioinformatics. (AU)