MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Evolution of RPCS, the major satellite DNA in rodents from the genus Ctenomys (Rodentia, Octodontidae) from the Iberá wetland, Corrientes Province, Argentina.
Autor/es:
CARABALLO DIEGO; BELUSCIO PABLO; M. GIMÉNEZ; C. BIDAU; MIROL PATRICIA; J. SEARLE; M ROSSI
Lugar:
Torino, Italia
Reunión:
Congreso; 12th Congress European Society for Evolutionary Biology; 2009
Resumen:
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The rodents of the genus Ctenomys (tuco-tucos)
conform an extreme case of chromosomal evolution in mammals. The species and forms of
tuco-tucos from the Iberá marsh (Corrientes province), are characterized by
named species with stable karyotypes, and a taxonomic undefined complex of
populations which exhibit high chromosomal polymorphisms. In previous work, the
relation between the nucleotide sequence and the expansion/contraction dynamics
of the major satellite DNA of tuco-tucos (RPCS) was studied, for different
karyomorphs of the genus. In this work, we studied the nucleotide variability
distribution and estimated the RPCS copy number, in specimens from the named
species that inhabit Corrientes: C. roigi, C. dorbignyi, C.
perrensi, and the forms from the C. sp complex. The study was
achieved using a PCR strategy to obtain RPCS genomic consensus sequence (gcs)
and also to estimate the RPCS c opy number per genome.
Genetic distances of RPCS gcs were calculated between pairs, and spanned in a
range of 0 12.93%. We corroborated the RPCS ancestral library hypothesis,
evidenced by the absence of total fixation in unique variants. This hypothesis
also finds support in the fact that all the intragenomic polytypisms share
variants with a strict RPCS consensus sequence obtained from a wide spectrum of
species.
RPCS copy number varies between 2-2,600 x103 copies per haploid genome. The
relationship between RPCS copy number, sequence variability and chromosomal
evolution resulted not trivial. This fact reveals that RPCS has gone through
complex processes during the cladogenesis, which are being elucidated in a
phylogenetic context.