Last Wednesday, Dr. Morton Rasmussen of the Natural History Museum of Denmark and his colleagues announced that they had completely sequenced the genome of an infant boy, buried ~12,600 years ago in Montana. A few weeks earlier, I’d been approached by an editor at Nature, who asked me if I and my mentor Deborah Bolnick would be interested in writing a companion paper that would analyze and contextualize their results. We agreed, and the paper was published in last week’s issue, alongside Rasmussen et al.’s work. Because it’s (unfortunately) behind a paywall, I’d like to summarize what we said in that paper for non-scientists. There are a lot of things to talk about with regard to this study, including a consideration of ethical issues and the media’s response, so I’m likely going to do several posts on it. This first post is mainly a discussion of how we interpret the results.
Archives For My research
I haven’t been writing as much here recently, because I’ve been working on a “News and Views” article for Nature….and now I can finally talk about it! Here’s a link to my article: http://www.nature.com/nature/journal/v506/n7487/full/506162a.html, and to the paper that it’s discussing: http://www.nature.com/nature/journal/v506/n7487/full/nature13025.html. In the next few days I’ll post something here to discuss the main points of the article (for those of you who can’t access it), and also my reaction to the media coverage that the study is getting.
It seems that every week there are exciting new findings from ancient DNA research. This is wonderful news, because we’re learning incredible things about the relationship between humans and Neandertals, the prehistory of ancient populations, and even previously unknown hominins. But on the flip side, we’re also seeing news reports of extremely questionable results, and I’ve gotten more than one inquiry recently from people excited or confused by them. I though it would be a good idea to write a bit about how regular people can figure out whether a study is legitimate or not.
The first step in distinguishing good ancient DNA studies from bad ones is the same as distinguishing pseudoscience from legitimate science in general: ask where the results are published. Are they in a peer-reviewed journal? Or does the author present it as “science by press release,” stating something like:
The next steps require you to know a bit about ancient DNA itself, and how research is conducted. What most casual readers may not understand is how difficult recovering DNA from ancient remains is….and how easily it can become contaminated.
The TL;DR version is that for an ancient DNA study to be considered authentic, at minimum it:
- Must be conducted in the proper facilities
- Must be conducted by personnel practicing sterile techniques
- Must utilize negative controls
- Must have a subset of results reproduced by an outside laboratory
- Must yield phylogenetically reasonable results (or produce extraordinary evidence to support unusual results), that match the characteristics of ancient DNA.
- Must conform to any additional standards necessary, depending on the sample and experimental design