Tate Mooy
BIOL 1010-006
ePortfolio #2
November 27, 2013
ePortfolio #2: De-extinction
Since the beginning of life on Earth, over 99% of all species to inhabit the planet have
since gone extinct. Extinction is not a new thing, it happens as life progresses, however, what
would happen if extinction could be reversed? Can mankind, with its’ advances in technology
and science, actually recreate species that lived thousands, perhaps millions of years ago?
In order to recreate or de-extinct a species, there’s a lot more to be done than gathering a
few DNA samples and mixing them in a Petri dish. In an article for National Geographic, Brian
Switek discusses three main methods for recreating extinct species that have been proposed so
far. They are cloning, reverse engineering, and breeding back. Cloning is the most popular and
discussed method. This is the method that’s portrayed by scientists recreating dinosaur species
in Jurassic Park. However, it’s very unlikely that recreating dinosaurs will ever be possible
because there have been no traces of DNA from any species that old (other than birds) that could
be used in order for the process to work. However, the process can work for species that are less
ancient and have enough DNA that complete genomes can be recreated. The species used as an
example is the thylacine, more commonly known as the Tasmanian tiger. In the process of
cloning, first, viable DNA must be gathered. Fragments of DNA are taken from miscellaneous
samples and compiled to create a complete thylacine genome. After a full genome has been
assembled, it has to be used to create a thylacine pup. Right now, there are two routes that could
be possible. The first is to combine a manmade thylacine cells nucleus with an egg from a
Tasmanian devil which has had its nucleus removed. The other is to take a line of DNA from a
Tasmanian devil and continually splice in sequences from thylacine DNA until the original
corresponding chromosomes have been replaced. Both of these methods could potentially result
in a viable thylacine pup.
In the interest of reverse engineering, Switek uses the passenger pigeon as an example.
First, a complete genome of the species has to be created, this is done by using fragments of
remaining DNA from museum specimens or other preserved sources. To assemble the genome,
scientists compare the DNA of the passenger pigeon to a distant cousin, the rock pigeon, in order
to identify any genetic mutation that would be distinct to the passenger pigeon. Mutations
mentioned are that of a red breast and a longer tail. After the complete genomes have been
assembled, the next step is to make stem cells. In order to make stem cells, scientists must take
certain, key pieces of DNA from the passenger pigeon genome and swap them out with the
corresponding pieces of DNA in rock pigeon stem cells. After the stem cells have been modified
for the Passenger Pigeon, they must be converted into germ cells. Germ cells are what
eventually become sperm cells and eggs. The germ cells are inserted in eggs of rock pigeons.
When the eggs hatch, they will produce rock pigeons that carry egg and sperm cells of passenger
pigeons. When two of these rock pigeons, each carrying the germ cells of a passenger pigeon,
mate, the offspring would be a viable passenger pigeon.
The last method covered is breeding back. A process that is based on taking living
species and using strategic and selective mating to eventually restore the original genome and
anatomy of a species that has gone extinct. The animal talked about by Switek is an ancestor of
domestic cattle, the aurochs. The idea here is that by taking cattle and creating a guided,
selective program for mating to combine traits unique to the aurochs into one lineage, eventually
a cattle population with a high number of aurochs traits will progress, leading to the resurrection
of the species.
De-extinction is controversial topic with numerous pros and cons. One of the most
important benefits to resurrecting extinct species would be the scientific knowledge to be gained
from doing so. It would offer incredible insight to how species have evolved and what behaviors
and instincts were present in ancient animals. Another benefit would include the advance in
technology. Having the means for de-extinction could help with other biologic dilemmas such as
genetic engineering. Perhaps the biggest pro, however, is simply the wonder that lies in deextinction. How amazing would it be to have all these species that man has never interacted or
shared the Earth with walking right next to us? Like any scientific debate, though, there are a
number of cons that could come with de-extinction. The welfare of animals and mankind is one.
With new species and old species learning to interact, and then interact with humankind, all sorts
of trouble could lie ahead. Others include the interest of the Earth’s natural resources and the
environment. With old species being reintroduced, things have changed since they last roamed
and underlying effects of bringing them into an environment that progressed over thousands of
years are unknown.
In my opinion, I think de-extinction is incredible. I had no idea just how feasible the
ability to recreate extinct species actually was. I believe that we as humans are in debt to species
that have gone extinct because of us. Extinction is natural and will continue to occur, but I think
that as long there’s a possibility for the species we’ve pushed out of existence due to the
advancement of mankind, to have a second shot at their own progression, we should give it to
them. I also think de-extinction would be very valuable for educational and scientific purposes.
Considering that only 1% of all animals to ever live on the earth are currently sharing it with us, I
think there would be nothing cooler than to have the ability to see what that the other 99% were
like firsthand through the means of resurrecting them. Lastly, I support de-extinction just
because it’s flat-out awesome. Who knows, maybe I’ll be taking my kids to a “zoo of the past”
sometime in the future.