EPIGENETIC MARKS: Chemical modifications of DNA (methylation and hydroxymethylation) or of histone tails (methylation, acetylation, phosphorylation) contribute to the regulation of gene expression. THE SCIENTIST STAFF
Plummeting costs for sequencing technologies have made deciphering an organism’s genome nearly routine. However, not all cells exist in the quantity these methods require—typically a few thousand to a million cells. When looking at early embryogenesis, for example, researchers might have only a handful of cells to analyze.
Each cell becomes precious, explains Daniel Messerschmidt, a biochemist and principal investigator at the Institute of Molecular and Cell Biology, A*STAR Singapore. He and his colleagues wanted to explain the mechanism behind their supposedly genetically identical mutant mouse embryos’ strange phenotypic diversity. The reason wasn’t written in the DNA sequences, they suspected, but in epigenetic marks that modify gene expression. But with so few cells, “we had no way to show it,” he says. They needed a ...