My name is Jacob Harris, and I just finished my freshman year here at Earlham. I’m so excited to be part of this research. Mayeesha, the museum director Heather, and I are studying DNA from C. ohioensis, the ancient giant beaver. Because the DNA is so old, it’s incredibly unstable and difficult to sequence and study. We’re sampling some of the specimens in the Joseph Moore Museum, and then we’re going to Germany to work in a specialized aDNA (ancient DNA) lab!
The first two days of the project, we focused on learning background information about ancient beavers. We reviewed beaver phylogenies, and read current studies. Scientists are debating whether beaver populations in the Midwest and Southeast were the same species. These articles focus on the morphological differences, mainly altered bone structures in the skull and different dental patterns. Ancient beavers in Florida tend to have more smushed-shape skulls and broken lines on their molars, whereas beavers in the Midwest, the traditional C. ohioensis, have an elongated skull and jaw. John Iverson came by and gave us an anatomy lesson, which really helpful.
We hope that by sequencing the DNA we can add a genetic element to the discussion. Unfortunately, it’s very difficult to get DNA from ancient specimens. What little DNA is left is likely heavily contaminated with bacterial and human DNA, even with extensive precautions. Temperature changes and UV radiation fragment and destroy DNA as well, and so ancient DNA can be seriously damaged. Specimens in places with more stable temperatures tend to preserve DNA more effectively, and so we’re looking for specimens found underwater. One thing we hope to prove with this project is that we can get DNA from common specimens, which would set us up for further research. In this project, our methods are just as important as our findings.
Today we started the DNA extraction process. We took samples from areas of our specimens more likely to contain DNA, primarily dentine from the interior of molars and incisors, where odontoblasts grew new teeth cells. Between each sampling we cleaned our equipment with bleach and changed gloves, so hopefully we avoided contamination. We asked to borrow specimens from other museums, and they’re being shipped. We’ll take samples from them as well. I’m excited to find out if we managed to sample any DNA, and I can’t wait to go to Germany!