Our results give further insights into the mode of microsatellite evolution, and support the assumption of increased slippage rate with increased microsatellite length and a stabilizing effect of interrupting motifs for microsatellite regions consisting of perfect repeats.
Evolution of increased microsatellite and EST GC content was evident within the grasses.
Microsatellites have been associated with regions of increased recombination in a number of organisms, including yeast [ 48] and, to a lesser extent, mammals [ 49- 51].
Possible causes of increased aggressiveness of these tumours include increased levels of microsatellite instability from loss of function of mismatch repair genes (Sawhney et al, 2006), and positive cytosine-phosphate-guanine island methylator phenotype (CIMP) status (Arain et al, 2010).
As expected, there was a rapid decline of conserved microsatellites with increasing species number, regardless of the chromosome examined (fig. 3).
The recent availability of huge amount of sequence data for a wide range of organisms, together with new methodological developments of in silico mining of microsatellites, have tremendously increased the characterization of these markers [ 5], and will certainly catalyze the study of genomic distribution of microsatellites in eukaryotes.
When 1,871 (12%) mononucleotide microsatellites were included, the proportion of unigenes carrying microsatellites increased to 17.4%.
The msh-2 mutants also had elevated levels of microsatellite instability and increased rates of reversion of the dominant unc-58 e665) unc-58 e665
Previously, it has been found that the rates of microsatellite instability increased [ 43] and SHR decreased [ 44] with age in Arabidopsis plants.
We sought to investigate whether there was any pattern in the distribution and extent of microsatellite conservation at the chromosome level by counting microsatellites conserved in increasing number of species.
