Researchers mousing around with DNA

While in the past extinct species’ genomes have been used to understand the phylogenies of both extinct and living organisms, the spotlight has now been changed from just observing the sequence of the DNA to actually resurrecting it to discover the function of the genes within.

The Tasmanian Tiger (Thylacinus cynocephalus) was a carnivorous marsupial that was driven to extinction by hunters and the introduction of dogs. It was from preserved pouch young that researchers have been able to extract DNA, isolate the segment of interest, and inject it into the nuclei of mouse zygotes to successfully produce transgenic mice embryos.

But why go to all this trouble?

As part of this study, the sequences for the corresponding portions of DNA that control the production of cartilage in the mouse and Tasmanian tiger were compared. From this it was noted that certain components (nucleotides) of that piece of DNA differed between the two species, differences that were never seen when comparing the same portion of rat, mouse, and human DNA. Because changes did not occur between these extant species, it was accepted that if changes were seen, the DNA would not function correctly. However, by successfully achieving expression of the Tassie tiger’s DNA in the mouse, it has been found that those components that were thought to be essential are, in fact, not critical to its function.

So, from this kind of experimentation we can learn about the function of extant species’ genes, and assess the consequences of changes within them.

Not only that, but by being able to recognise the functional components of distinct species’ genomes, this can assist in putting together a ‘bigger picture’ of species evolution and the diversity of life.

Primary reference:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0002240

Secondary reference:
http://www.austmus.gov.au/thylacine/index.htm