Insights on the composition and evolution of the satellitome in the A and B Arachis genomes

SAMOLUK SS; VAIO M; CHALUP, LAURA M. I.; ROBLEDO G.; BERTIOLI DJ; JACKSON SA; SEIJO JG

Conferencia; 10th International Conference on Advances in Groundnut Research through Advances in Genomics and Biotechnology (AAGB); 2018

Satellite DNA (satDNA) is a major component of the heterochromatic regions of eukaryote genomes and usually shows a high evolutionary dynamic, even among closely related species. Cytogenetic and molecular evidences suggest that A. duranensis (A-genome) and A. ipaensis (B-genome) are the wild diploid species (2n=2x=20) most likely involved in the origin of the allotetraploid A. hypogaea. One of the most striking karyotypic differences between these progenitors is the relative content of heterochromatin; i.e. while A. duranensis have conspicuous centromeric bands in most chromosomes, A. ipaënsis chromosomes are deprived of them. The aim of this study was to provide information on the major changes underwent by satDNAs (the satellitome) during their genome differentiation. SatDNAs were identified using a high-throughput analysis using the satMiner pipeline. In addition, the chromosome distribution of the most abundant satDNA families was analyzed by Fluorescent in situ hybridization (FISH). Our results suggest that both, A and B genomes, share most of the satDNAs but they differ in the representation of some families, in accordance with the satDNA ?library hypothesis?. Only few of the isolated satDNAs were amplified and constitute the major components of the heterochromatic bands. This research provides complementary information to the genome analyses that are being carried out in Arachis, and constitutes the basis for understanding the satDNA evolutionary dynamics in diploid and allotetraploid Arachis genomes and their impacts on karyotype evolution.