Monitoring RNA levels in blood yields dynamic picture of fetal development

Recent research has shown that tiny fragments of DNA circulating in a person's blood can allow scientists to monitor cancer growth and even get a sneak peek into a developing fetus' gene sequences.

But isolating and sequencing these bits of genetic material renders little insight into how that DNA is used to generate the dizzying array of cells, tissues and biological processes that define our bodies and our lives.

Now researchers at Stanford University have moved beyond relying on the static information delivered by DNA sequences in the blood. Instead, they've generated a much more dynamic picture by monitoring changing levels of another genetic material -- RNA -- in the blood. It's the biological difference between a still photo and a video when it comes to figuring out what the body is doing, and why.

"We think of this technique as a kind of 'molecular stethoscope,'" said Stephen Quake, PhD, professor of bioengineering and of applied physics, "and it's broadly useful for any tissue you care to analyze. There are many potential practical applications for this work. We could potentially use it to look for things going wrong in pregnancy, like pre-eclampsia or signs of preterm birth. And we hope to use it to track general health issues in various organs."

Quake and his colleagues combined the use of high-throughput methods of microarrays and next-generation sequencing to analyze the sequences and relative levels of RNA in the blood of pregnant women, healthy volunteers and Alzheimer's patients. By focusing on RNA messages encoding proteins known to be produced only in certain tissues, they were able to track the development or health of particular organs throughout the body.