by David Biello
March 26, 2013
ScientificAmerican.com
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| Passenger Pigeons |
Controversy over the
de-extinction of species has taken the scientific community by storm. Recent
developments in genetics and cloning have lead to extensive talks
about the pros and cons of reviving extinct species
or endangered one. Recently, developments in reviving the extinct
passenger pigeon have been made. At one point, these birds were densely populous
in the United States; however, they have gone extinct, leaving DNA samples
behind. Ben Novak, a de-extinction scientists, has claimed
that bringing back this species would help with,
"rejuvenating resources and allowing other animals to
thrive... [also] there is more passenger pigeon habitat every year." The
production of once-extinct animals has lead to much debate about the
effectiveness of it, in relation to how it is raised. Since there are
no other members of this species, it would grow up to develop different
mannerism that those of its ancestors. Also, it would no doubt lead to genetic
mixing. Various species, including us humans, all have mixed genetics from a
variety of ancestors. Scientists working on this case would have
to mix genetics to produce a full genome, using
a technique called gene splicing. This uses the enzyme Cas9 to sew
together segments of DNA to create certain traits. It is proposed that if one
can determine which genes cause members of similar species
to express different traits, than the genetics of one organism can be
modified to suit another. It is also important to take into account
the importance of epigenetics in determining gene expression. Dr. David
Ehrenfeld of Rutgers University compares this phenomenon to literature.
He has stated that, "all of the words of Hamlet are
in the dictionary, Hamlet does to fall
out of it. A strand of DNA can be read in hundreds or even thousand ways."
Novak has stated that, "breeding [the passenger pigeon] is the
greatest technical challenge [but it] pales in comparison to the natural
passenger pigeon." Techniques of spray painting birds have been employed
to encourage correct gene expression have been proposed to counteract
epigenetic expressions. Overall, reviving extinct species is a very complex
process, which includes many issues with presenting the 'true' form of
that species.
The emerging field of
extinction biology provides fascinating glances into the function of
ecosystems, as well as the very function and structure of species. The complex
processes of genetic expression are also very compelling and could potentially
play a major role in future genetic engineering. In my opinion, both
society and the environment could greatly benefit from the
revival of some extinct species. However, top predators and large consumers
should not be produced for reintroduction into the wild, since they could
greatly change the structure of the food and energy pyramids. In the case
of the passenger pigeons, their re-introduction into the wild perfectly
suits the current environmental situation: much of their old habitat is
returning, therefore they can reestablish niches relatively quickly,
as well as lead to the creation of greater ecosystem resilience and
diversity. Also, the appearance of this development in the media
could greatly raise awareness for extinction and environmental concerns.
However, I do acknowledge there are many risks to creating modern members of
this extinct species. To some degree, we would eventually be creating an entirely
new species, since their ancestors’ customs and characteristics are
unknown to them. This could potentially lead
to unforeseen disturbances in
ecosystems, disrupting their state of equilibrium. In addition, the
article addresses the possibility that these birds could potentially
carry new strains of viruses. In conclusion, the revival of passenger
pigeons could greatly help the ecosystem, while generating
public awareness; however, we must not forget the dangers
of undertaking this reintroduction.
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