It seems as if scientists are announcing that they've sequenced the genome of yet another species just about every week. It's become so common that back in 2010 science journalist Carl Zimmer wrote about the term YAGS: 'Yet-Another-Genome Syndrome'. On his blog, he wrote, "There’s a certain kind of headline I have become sick of: Scientists Have Sequenced the Genome of Species X!" Well ... I'm here to tell you that scientists have sequenced the genome of the domestic ferret!
Big deal, you say. But the ferret is actually quite an important animal and the information derived from its genome is poised to help researchers better understand not just human health and disease, but also wildlife health.
Despite the fact that ferrets diverged from humans some two million years earlier than mice, the rodents went on to evolve quite a bit on their own. As a result, as University of Washington researcher Xinxia Peng wrote in Nature Biotechnology this week, there is "less genetic divergence between humans and ferrets than between humans and mice". The mouse may be the workhorse of modern biomedical research, but the ferret has become quite important.
In particular, ferrets are useful to scientists who study respiratory diseases like the flu, coronavirus, nipah virus, morbillivirus and others. For influenza, that's both because the means of infection are similar, since ferrets and humans share similar lung physiology, and because the patterns of transmission are similar, with the disease passing from sick to healthy individuals. And while influenza viruses are common across mammals and birds, both humans and ferrets are susceptible to the same strains.
So after Peng sequenced the ferret's genome, researchers from the Kawaoka lab at the University of Wisconsin-Madison went about exposing 21 juvenile ferrets to one of two strains of pandemic influenza: either the H1N1 Spanish flu of 1918, which killed 25 million people worldwide, or the H1N1 swine flu that spread in 2009-2010 and which is still circulating today. Samples were then taken from the ferrets' windpipes and lungs after infection, so the team could analyse the RNA from the collected cells.
“The information derived from the ferret genome is poised to help researchers better understand not just human health and disease, but also wildlife health.”
The genome sequencing has now allowed researchers to verify that ferrets and humans are also similar enough on a genomic level to make them useful as a comparison species. What's more, the RNA analysis showed that ferrets and humans express the same genes, in the same tissues, in the same patterns, in response to the two influenza viruses. This sort of detailed understanding of the dynamics of flu infections and the ways in which different parts of the body respond differently will allow human physicians to get a better understanding of how flu works in our own species as well.
But it isn't just humans who stand to benefit from this research. Domestic ferrets (Mustela putorius furo) are also closely related to the wild black-footed ferrets (Mustela nigripes), a highly endangered North American species. In 1987, there were just a few dozen black-footed ferrets left in the world; they were considered extinct in the wild. But a concerted captive breeding effort spearheaded by the US Fish and Wildlife Service and several zoos has meant that there are now more than one thousand mature, wild-born individuals across eighteen populations in the American West. Six of those populations are healthy enough that they are self-sustaining.
But as is the case for any population of animals that are descended from a small set of founders, black-footed ferrets suffer from severe inbreeding. Congenital defects, such as impaired immune systems and abnormalities in male fertility, are now common throughout the species. Peng and his colleagues hope that the genomic information they've made available on domestic ferrets will aid wildlife biologists in identifying the genetic basis of these defects in wild ferrets so they might be somehow mitigated through the ongoing captive breeding program.
Top header image: Tetting, Flickr