We use animals in research because they’re so similar to humans. So what can be gained from using marsupials, such as opossums and wallabies, that are so far from humans on the evolutionary family tree? James Turner, a researcher at the MRC National Institute for Medical Research (MRC NIMR), tells us why finding similarities in these more distant relatives can lead to important and surprising results.
For many years, scientists have used laboratory mammals such as monkeys, mice and rabbits to understand how human diseases develop and how they can be treated. The DNA make-up, or genome sequence, of these animals is very similar to that of humans, and we’re all members of the largest class of mammals (the ‘eutherians’), so they make good experimental models.
But during the past few years, my group at the MRC NIMR, along with other researchers, have started using a more unusual type of mammal, the ‘metatherian’, or marsupial, to understand human biology. Marsupials, such as opossums and wallabies, can provide us with a level of insight that other mammals cannot. Read more
A male opossum in its cardboard tube (Image copyright: NIMR)
Mice, rats, macaques, ferrets … there are quite a few well-known laboratory mammals. But opossums? What can these solitary marsupials offer science? Katherine Nightingale went to the MRC National Institute for Medical Research (MRC NIMR) to find out.
It’s Thursday morning at the MRC NIMR and the institute’s 100 opossums are going about their usual business. Being nocturnal, that means not a lot. In their room, most of the female opossums are burrowed into their nests, big eyes peering out from under shredded paper. Next door, the males are settling into their new double-height cages, tails dangling from one end of their cardboard tubes and long noses protruding from the other.
Native to South America, the grey short-tailed opossum (Monodelphis domestica), also known as the laboratory opossum, is a fairly unusual research animal. The NIMR is the only place in the UK to keep a colony, with other larger colonies at the University of Trieste in Italy, and the Texas Biomedical Research Institute in the United States.
Yet in recent years, scientists have begun to recognise just how useful the opossum can be to medical research. Being mammals, they share many genes and biological processes with humans, and so can be used as model animals in much the same way as mice or rats.
But opossums have other tricks up their sleeves. They are marsupials, meaning their branch of the mammal family tree split from ours around 148 million years ago. This means they differ from us in crucial ways, and by comparing these differences, researchers can learn more about the biology of people. Read more