The DNA’s Hidden Code
By Davide Castelvecchi
Scientists have discovered what appears to be an additional language hidden in the DNA code together with the language of genes.
Geneticists have long known that it’s not only your genes that matter, but also whether they are active or not. For example, recessive genes are often completely dormant. But other factors determine the activation of a gene (and some of these factors can even be hereditary, such as epigenetic information). One of the most important such meachanisms may be that our DNA is not a freely floating double strand, but a tight packing of yarns wound around proteins called histones.
This packing determines in part which segments of DNA are accessible to the molecular machinery of the enzymes that activate a gene. Scientists have long wondered if the DNA’s own code somehow helps determine the geometric arrangement of the histones.
In a paper published in Nature in August, a team led by Eran Segal, a mathematician at the Weizmann Institute in Israel, and Jonathan Widom, a biochemist at Northwestern University, near Chicago, revealed a code made of particular sequences of DNA letters that make it physically easier for a particular section of DNA to wrap around histones. Their studies focused on yeast, but are likely to apply to all plants and animals.