Insights on the Composition and Evolution of the Satellitome in the A and B Arachis Genomes

SAMOLUK, SERGIO S.; VAIO M; CHALUP, LAURA ; GERMAN ROBLEDO; D. BERTIOLI; S. JACKSON; GUILLERMOSEIJO

Conferencia; AAGB 2018 Conference; 2018

SatelliteDNA(satDNA)isamajorcomponentoftheheterochromaticregionsofeukaryotegenomes and usually shows a high evolutionary dynamic, even among closely relatedspecies.CytogeneticandmolecularevidencessuggestthatA.duranensis(A-genome)andA.ipaensis (B-genome) are the wild diploid species (2n=2x=20) most likely involved in theorigin of the allotetraploid A. hypogaea. One of the most striking karyotypic differencesbetween these progenitors is the relative content of heterochromatin; i.e. while A.duranensis have conspicuous centromeric bands in most chromosomes, A. ipaënsischromosomesaredeprivedof them.Theaimof thisstudywas toprovideinformationonthe major changes underwent by satDNAs (the satellitome) during their genomedifferentiation. SatDNAs were identi4ied using a high-throughput analysis using thesatMinerpipeline.Inaddition,thechromosomedistributionofthemostabundantsatDNAfamilieswasanalyzedbyFluorescentinsituhybridization(FISH).Ourresultssuggestthatboth,AandBgenomes,sharemostofthesatDNAsbuttheydifferintherepresentationofsomefamilies,inaccordancewiththesatDNA?libraryhypothesis?.OnlyfewoftheisolatedsatDNAs were ampli4ied and constitute the major components of the heterochromaticbands.Thisresearchprovidescomplementaryinformationtothegenomeanalysesthatarebeing carried out in Arachis, and constitutes the basis for understanding the satDNAevolutionarydynamicsindiploidandallotetraploidArachisgenomesandtheirimpactsonkaryotypeevolution.