New techniques let scientists zero in on individual cells

EW YORK (AP) — Did you hear what hap pened when Bill Gates walked into a bar? Everybody there immediately became millionaires — on average.

That joke about a very rich man is an old one among statisticians. So why did Peter Smibert use it to explain a revolution in biology?

Because it shows averages can be misleading. And Smibert, of the New York Genome Center, says that includes when scientists are trying to understand the basic unit of life, the cell.

Until recently, trying to study key traits of cells from people and other animals often meant analyzing bulk samples of tissue, producing a mushed-up average of results from many cell types. It was like trying to learn about a banana by studying a strawberry-blueberry-orange-banana smoothie.

In recent years, however, scientists have developed techniques that let them directly study the DNA codes, the activity of genes and other traits of individual cells. The approach has become widely adopted, revealing details about the body that couldn’t be shown before. And it has opened the door to pursuing an audacious goal: listing every cell type in the human body.

“Single-cell analysis is crucial for a comprehensive understanding of our biology and health,” Dr. Francis Collins, the director of the National Institutes of Health, declared recently.

In fact, the journal Science named the techniques that allow single-cell tracking of gene activity over time in developing organisms and organs as its “breakthrough of the year” for 2018. Its announcement declared, “The single-cell revolution is just starting.”

A SLEW OF DISCOVERIES

Even complicated animals like us are really just massive communities of cells, each taking on a particular role and working with its neighbors. An average adult human has 37 trillion or so of them, and they’re surprisingly varied: the inner lining of the colon, for example, has more than 50 kinds of cells.