By Dr. Rowland, Paleontologist & Las Vegas Natural History Museum Lab Manager
The 1993 movie Jurassic Park (yes, it was really 28 years ago ) introduced us to the idea of obtaining DNA from fossils and doing interesting things with it. The reality is that dinosaurs lived so long ago―more than 66 million years (except for the ones we now call birds)―we are unlikely to ever recover intact T. rex DNA. Until very recently the oldest fossil DNA ever obtained was about 700,000 years old, from the fossil leg bone of a horse. But that record has just been broken.
In a paper published this month in the journal Nature, an international team of scientists announced the successful sequencing of DNA from mammoths that lived in Siberia ~1.2 million years ago. Not only does this set a new record for the age of fossil DNA, the details reveal new information about the evolution of Columbian mammoths, a species that was restricted to North America. (1) The first image is an artist’s reconstruction.
Columbian mammoths (Mammuthus columbi) were the largest elephants that ever lived. They were about 13ft tall, with tusks up to 16ft long. They were abundant in Southern Nevada during the Pleistocene Ice Age. Here at the Museum, we are studying mammoth bones and tusks that we excavated in Amargosa Valley, in Nye County, northwest of Pahrump. (2) The second image is a drone view of our UNLV/LVNHM excavation site. The white bundles in the middle of the photo are plaster jackets containing mammoth tusks and bones.
The new genomic data provide a deep historical context for the ancestry of this species. The data reveal that two distinct lineages of mammoths existed in Siberia 1.2 million years ago. It turns out that DNA from Columbian mammoths contains admixtures of DNA from both lineages. The researchers concluded that Columbian mammoths are a hybrid species, having been derived from hybridization of the two Siberian lineages.
We may never be able to recover dinosaur DNA, but this new study suggests that paleogenomic data from Ice Age species will continue to be recovered. These data will reveal the deep history of plants and animals living today, as well as the history of species such as mammoths, from the relatively recent geological past.