Comparative analysis of repetitive DNA in a dysploid group of Phaseolus beans

FERRAZ ME (FERRAZ MARIA EDUARDA); RIBEIRO, T. (TIAGO RIBEIRO); SADER, M. A. (MARIELA ANALÍA SADER); PEDROSA-HARAND, A. (ANDREA PEDROSA-HARAND)

Mendoza

Congreso; Congresso Latinoamericano de Genética; 2019

Sociedad Argentina de Genética

Repetitive sequences are fast evolving elements responsible for variation in genome size and structure. Phaseolus L. comprises small-genome species (mean 685 Mpb) with a group (the Leptostachyus group) showing a dysploid karyotype (from 2n = 22 to 2n = 20) due to a centric insertion, in combination with many translocations. In this work, we aimed to investigate whether these structural rearrangements were associated with diversification on the repetitive landscape in the Leptostachyus group. For that, we analysed the repetitive fraction of two species (P. leptostachyus and P. macvaughii) in comparison to 11 other with the standard karyotype (2n = 22). The sequences were clustered by similarity using the RepeatExplorer pipeline and the TAREAN tool was applied for identification of satellite repeats. The most abundant repeats were located in situ. The Ty3/gypsy/Chromovirus lineage was the main element in all species and had preferential distribution at pericentromeres. A reduction in the abundance of Tekay in P. macvaughii (0,52% vs. 5,74% in P. leptostachyus) and SIRE (Ty1/copia) in P. leptostachyus (1,9% vs. 4,03%) was observed, suggesting a faster turnover of these elements in this group. Shared satellite DNAs revealed different distribution patterns among species. While most satDNAs were centromeric or subtelomeric, one family showed a dispersed distribution in this group. The differences in abundance and distribution observed in P. macvaughii and P. leptostachyus suggest a possible association of these repeats and the frequent chromosomal rearrangements in the group.