In reviewing the data produced by the study -- information on the methylation of three billion base pairs of DNA -- the scientists were able to identify previously unknown patterns of DNA methylation. They identified cases in which DNA methylation appeared to enhance, rather than repress, the activity of the surrounding DNA, and found evidence to suggest a role for DNA methylation in the regulation of mRNA splicing.

"We produced a very large amount of data," said Loring, "but it actually simplifies the picture. We identified patterns of many genes that are methylated or de-methylated during differentiation. This will allow us to better understand the exquisitely choreographed changes that cells undergo as they develop into different cell types."

Louise Laurent of TSRI and the University of California, San Diego, one of the first authors of the study, added, "The data are publicly available, and we are looking forward to learning what other scientists discover from using this information for their own studies on individual genes, embryonic development, and stem cells."

"This is definitely an exciting finding in the field of stem cell research," added co-first author Eleanor Wong, who is a graduate student from the GIS in Dr Wei's lab. "Using this knowledge, scientists can now survey different cell types and developmental pathways, identify the genes affected, and characterize the functions of these genes in the process of differentiation. It's all very exciting!"

SOURCE The Genome Institute of Singapore and The Scripps Research Institute