DNA architecture, novel forensics offer new clues

It’s one thing to catalog each chemical unit of DNA that makes up the human genome. It’s another thing entirely to understand how that genetic material is folded up inside a living cell — and then decoded, manipulated and used.

Achieving that understanding is the task of the architectural scholars of molecular biology, scientists who describe the loops and other yogic postures that DNA displays inside the cramped space of a cell’s nucleus. This architecture has important implications for function, perhaps by arranging the genetic furniture to enable one cell to operate as a liver cell and another to work as a skin cell. But even this 3-D appreciation of the genome is limited, as science writing intern Sarah Schwartz writes. Researchers must also contemplate a fourth dimension: genome morphing over time.

Scientists are now drawing up plans to map the 4-D genome, Schwartz reports. Besides acquiring deeper understanding of this fascinating bit of biology, the project will provide clues to how misfolding of the genome can lead to disease and what role it may play in aging.

Forensic scientists are searching for better clues as well, although their interest is in more reliable identification of crime suspects. Meghan Rosen reports on some of the limits of well-known methods, such as fingerprint analysis, and how scientists are seeking to improve them. Rosen also describes new ways that detectives might solve whodunits with aid from the burgeoning field of microbial forensics. Along with our hair and finger marks, we may leave behind idiosyncratic collections of microbes, which may one day help rule out suspects. Body odors may also inform both the search for and prosecution of criminals, researchers say. That’s assuming that scientists can establish just how different each individual is in terms of odor and microbes so these clues can be used as reliably as DNA evidence to identify someone.

Going from theory to practice is always rife with problems, be it shifting from the sequence of DNA’s letters to observing its dynamic machinations in a cell or from a potential identity marker in the lab to a piece of courtroom evidence. But the journey offers what any good mystery should: a chance for surprising discoveries.