Popping your leftovers into the freezer is your best bet for saving them for later. Keeping things cold is also the best method for preserving DNA molecules. To learn about the tools and techniques for the world-class care of tissue samples used for DNA research, I travelled to a basement in New York City.
The American Museum of Natural History looms large over the west side of New York’s Central Park. Behind its grand granite façade, creatures of all kinds are on public display. Walking through this museum—one of the world’s largest—is a rich experience of our planet’s animals, plants and minerals.
Behind the scenes, however, there is much more to the museum than its impressive exhibits. Just like the Canadian Museum of Nature, the American Museum of Natural History (or simply “the AMNH”) houses large collections of animal, plant, fossil and mineral specimens. The museum’s research scientists—and researchers from around the world—use these collections to better understand the diversity of life on Earth.
Increasingly, scientists use information stored in DNA molecules to study biodiversity. Ideally, these DNA molecules are extracted from tissue samples specifically collected for this purpose. These tissue samples need special care and storage conditions to preserve the valuable molecular information. The key is cold temperature—MUCH colder than your home freezer can provide.
On the hunt for supercold freezers, I walked past the AMNH exhibits, through an inconspicuous brown door, and down a flight of stairs. Now in the basement, a maze of utilitarian hallways and workshops led me to the Ambrose Monell Cryogenic Collection.
Julie Feinstein, the manager of the collection, keeps careful watch over the large insulated stainless steel vats that house roughly 100 000 tissue samples. Eight inches of liquid nitrogen in the bottom of each vat keeps the samples at a seriously chilly −160°C. At this temperature, most molecular movement stops, which prevents the degradation of the samples. The information of DNA is preserved in perpetuity.
This cryogenic collection, like other museum collections, is not a static assemblage of objects locked away for eternity. Specimens come and go, arriving with researchers back from the field or sent out to curious scientists anywhere in the world.
Keeping track of incoming and outgoing samples and the data associated with them requires meticulous care. I spent two days observing this careful work as I peered over the shoulders of Svetlana and Nisa, the collection’s technicians and frontline workers. They deftly handled the traffic of samples, which are stored in small, barcode-labelled, polypropylene tubes.
Cold is the key for a good tissue collection, but so too is organization. This is one of many important lessons learned during my time in the New York City basement.
My visit was part of a knowledge-gathering process that is just getting started. The Canadian Museum of Nature would be a natural home for a cryogenic tissue collection.
Before we roll cryovats into our research and collections facility, we need to be well versed in the best way to establish and manage such a collection. If all goes well though, we will have the coldest and best organized freezers in the country.