An efficient chemical method to generate repetitive sequences depleted DNA probes

High-throughput sequencing of methylated cytosine enriched by modification-dependent restriction endonuclease MspJI

Background

As a well-known epigenomic modification, DNA methylation is found to be common in plants and plays an important role in many biological processes. Relying on the unique feature of methylation-dependent digestion, the family of methylation-requiring restriction-like endonuclease, such as MspJI and its homologs, was suggested for a potential usage in methylation detection.

Results

In this study, we combine MspJI digestion and electrophoretic band selection with next generation high-throughput sequencing technology to detect 5-methylcytosines in Arabidopsis genome. By developing a bioinformatics workflow to attribute the CNNR sites recognized by MspJI to the reference genome, we fulfilled the systematic assessment of this method.

Conclusions

According to the assessment, here we provide the method for generating a detailed map of plant methylome that could be feasible, reliable and economical in methylation investigation.

Microdissection and chromosome painting of X and B chromosomes in Locusta migratoria

Acquisition of knowledge of the nature and DNA content of B chromosomes has been triggered by a collection of molecular techniques, one of which, microdissection, has provided interesting results in a number of B chromosome systems. Here we provide the first data on the molecular composition of B chromosomes in Locusta migratoria, after microdissection of the B and X chromosomes, DNA amplification by one (B) or two (X) different methods, and chromosome painting. The results showed that B chromosomes share at least two types of repetitive DNA sequences with the A chromosomes, suggesting that Bs in this species most likely arose intraspecifically. One of these repetitive DNAs is located on the heterochromatic distal half of the B chromosome and in the pericentromeric regions of about half of the A chromosomes, including the X. The other type of repetitive DNA is located interspersedly over the non-centromeric euchromatic regions of all A chromosomes and in an interstitial part of the proximal euchromatic half of the B chromosome. Chromosome painting, however, did not provide results sufficiently reliable to determine, in this species, which A chromosome gave rise to the B; this might be done by detailed analysis of the microdissected DNA sequences.