Chromosomes the 46 tightly-wrapped packages of genetic material in our cells are iconically depicted as X-shaped formations. However, those neat X's only appear when a cell is about to divide and the entire contents of its genome duplicated. Until now researchers have not been able to get a good picture of the way that our DNA some two meters of strands all told is neatly bundled into the nucleus while enabling day-to-day (non-dividing) gene activity. A combination of new techniques for sequencing DNA in individual chromosomes and analyzing data from thousands of measurements has given us a new picture of the 3-D structures of chromosomes. This method, the result of an international collaboration, which was recently reported in Nature, promises to help researchers understand the basic processes by which gene expression is regulated and genome stability maintained.
Prof. Amos Tanay of the Weizmann Institute's Computer Science and Applied Mathematics and the Biological Regulation Departments develops advanced computer algorithms for analyzing genomic datasets, which can run to billions of bits of information. He and his team, including PhD students Yaniv Lubling and Eitan Yaffe, joined forces with Dr. Peter Fraser of the Babraham Institute, UK, in an attempt to resolve chromosomal architectures at an unprecedentedly high resolution. Rather than the traditional microscopy techniques, they harnessed the power of modern high-throughput DNA sequencing. Fraser and his team developed a sophisticated sequencing method for taking thousands of measurements of the contacts between genes inside single cells. While these techniques vastly improve upon approaches that average the conformations of millions of chromosomes, the data generated from just the few trillionths of a gram of DNA present within a single cell can only be interpreted by advanced statistical methods. Tanay and his team performed the complex computer analysis that turned millions of DNA
|Contact: Yivsam Azgad|
Weizmann Institute of Science