engleski

ELUCIDATION OF THE GENOMIC SPECIFICITY OF THE THREE SUBGENOMES IN THE ALLOTRIPLOID Allium x cornutum USING MINISATELLITES

To investigate how the repeat composition of the allotriploid Allium x cornutum and its three parental species from the Allium sect. Cepa, diverged, we applied low coverage next-generation sequencing and read clustering to their four genomes. To identify possible genomic changes, we focused on satellite DNA as the most rapidly evolving part of the genome. By applying comparative bioinformatics and fluorescent in situ hybridization (FISH), we uncovered three satellite DNA families that were shared among allotriploid and its parental species. Furthermore, we identified a satellite DNA class with a monomer length of 97 pb that is relatively more abundant in the allotriploid than in any of the three parental species. This type of minisatellite was mapped by FISH in the pericentromeric region of the second largest chromosome pair of A. cepa. In the karyotype of triploid A. x cornutum, two different chromosomes carried three signals: one locus in the pericentromeric region of the longer chromosome and two loci in both the pericentromeric and intercalary positions of the shorter chromosome. Ongoing FISH mapping in the other two parental species (A. roylei and A. pskemense) will answer the question of whether the dynamics of this minisatellite may have produced some type of genomic novelties in the allotriploid karyotype. Mapping of minisatellite loci will provide a cytogenetic overview of the history of parental tri-subgenome distribution in their allotriploid.

Allium sect. Cepa, minisatellites, polyploidy, genome evolution

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