INVESTIGADORES
SEIJO jose guillermo
congresos y reuniones científicas
Título:
Karyotype evidences of genome differentiation at diploid and polyploid levels in Arachis species (sect. Arachis). Simposio, Cytogenomic.
Autor/es:
J. G. SEIJO; SAMOLUK, S; CHALUP, L.; GERMÁN ROBLEDO
Lugar:
Montevideo, Uruguay
Reunión:
Conferencia; XVII Congreso Latinoamericano de Genética,; 2016
Institución organizadora:
Sociedad Latinoamericana de Genética
Resumen:
Section Arachis is composed of diploid species (2n=20, 18) with A, B, D, F, G or K genomes and two AABB tetraploids, the peanut and its direct antecessor A. monticola. GISH analyses revealed the existence of a high genomic differentiation. By contrast, genetic maps and sequencing revealed a high colinearity among the species assigned to A and B genomes. The transference of molecular markers is also very high among the genomes. On these bases, it was hypothesized that the repetitive fraction has played an important role in the differentiation of the genomes and allopolyploidization. This was tested by the isolation, characterization, quantification and chromosome mapping of different repetitive sequences in representative species of each genome formula. The global pattern of 5-methylcytosine was also analyzed. The retroelements Ty3-Gypsy and LINES, the CACTA-like transposons, and the satellite sequence TR2 showed a differential representation in dot-blot analysis and genome distribution by FISH at the diploid level. The distribution pattern of the 5-methylcytosine by immunocytochemistry was distinctive between the A and B genomes. Comparing the allotetraploids with its diploid progenitors, all the markers analyzed evidenced clear genome additivity. However, the cytosines of the B-genome of the tetraploids appeared hipermethylated with respect to its wild progenitor. These results evidenced that changes in the repetitive fraction and in the epigenetic patterns had played a role in genome differentiation at diploid level. However, the allopolyploidization did not affect the sequence arrangement in the AABB taxa, but its trigger the massive hypermethylation of the B genome