One of the strangest episodes in the history of biology occurred in 1953. A physicist named George Gamow, who is best known for his work on the Big Bang, sat down and read a new paper by two biologists named James Watson and Francis Crick. They reported that DNA is arranged as a double helix. Gamow then wondered how DNA encodes proteins. DNA used four “letters” in its genes, while proteins are built from a chemical alphabet of twenty amino acids. He realized that the question turned life into a problem in cryptography. Continue reading “The Code of Life: My New Feature for Nautilus Magazine” →

A simple question deserves a simple answer. How many cells are in your body?

Unfortunately, your cells can’t fill out census forms, so they can’t tell you themselves. And while it’s easy enough to look through a microscope and count off certain types of cells, this method isn’t practical either. Some types of cells are easy to spot, while others–such as tangled neurons–weave themselves up into obscurity. Even if you could count ten cells each second, it would take you tens of thousands of years to finish counting. Plus, there would be certain logistical problems you’d encounter along the way to counting all the cells in your body–for example, chopping your own body up into tiny patches for microscopic viewing.

For now, the best we can hope for is a study published recenty in Annals of Human Biology, entitled, with admirable clarity, “An Estimation of the Number of Cells in the Human Body.”

Continue reading “How Many Cells Are In Your Body?” →