July 1, 2013,Philly.com
by Matt Soniak-- Not every line of scientific enquiry will make your teeth
whiter or improve the gas mileage on your car, but that doesn't render
scientific endeavors that don't deal with optimum petroleum efficiency or
dental cleanliness entirely worthless. Where the value in a specific enquiry
lies can be hard to pin down for the everyman, though, especially if news
stories about said research don't make that clear.
For their tuatara genome sequencing project, a
group of scientists in New
Zealand are cutting out the middleman and
blogging their way through their research. Their first post is "Why
sequence the tuatara genome?" So, straight from the horse's mouth, here's
why they're looking at the genome of lizards' cousins (SPOILER ALERT:
Evolution).
To understand why a tuatara genome is such a
tantalising prospect for scientists you need to know how the tuatara relates to
other reptiles. All life on earth is connected by a shared evolutionary
history. When biologists try to organise the diversity of life on earth, we
reconstruct that history by finding groups of species that all descend from a
shared common ancestor.
You sometimes hear people mistakenly call tuatara
“living dinosaurs”. In fact, as you can see in the figure above, tuatara are
much more interesting than that. If you want to study a living dinosaur you
only need to look out the nearest window. Modern birds descend from one branch
in the diverse group we call dinosaurs, but each of those ten thousand species
are dinosaurs. The tuatara, on the other hand, are the only living members of a
lineage that separated from other reptiles more than 200 million years
ago.
By placing modern organisms in the context of their
evolutionary history, we can work out which traits were present in ancestral
species, and reconstruct the changes that gave rise to modern ones. As the
tuatara is the only living witness to hundreds of millions of years of
evolution, its genome sequence will be immensely valuable in understanding the
genetic changes that have allowed reptiles to evolve and diversify.
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