Genetic Science and Elusive Elephants - Genomic Pursuit, Illumination Magazine


Uploaded by IlluminationMagazine on 12.04.2012

Transcript:
My name is Lori Eggert. I am an associate professor of biological sciences at the
University of Missouri.
For many years my research team and I have used genetic tools to learn more
about elephants and other elusive or dangerous animals around the world.
Many of the techniques my team and I have developed are focused on elephant populations
in Africa and in Asia.
Our goal is to use these techniques
to collect and analyze information that will help us learn about the ecology of
these species
and provide data that will help wildlife managers make better decisions about
endangered animals and habitats they occupy.
A 2006 study that my lab team and I conducted in collaboration with
the Wildlife Conservation Society
using funding from the U.S. Fish and Wildlife Service shows how this works.
The construction of a hydropower dam on the Nam Theu river was about to
severely restrict the available habitat for the Asian elephants of the Nakai
Plateau in Laos.
It was crucial that we have a better understanding of the size, health and
genetic diversity of the elephant herd
to allow the the government of Laos to make sound decisions about managing the
population
during and after dam construction.
We began the project with a dung count.
This involved breaking the habitat into 16 geographical blocks
ranging from two to eight square kilometers. Members of our field research team
visited each block once a month
noting the number and locations of the dung piles they encountered.
Since the size of elephants corresponds directly with their age
and bigger elephants leave larger dung,
we measured the conferences of "boli" - this is the name we use to describe an
individual piece of dung -
that we found in each pile.
We also collected samples for genetic testing in the lab.
We learned from the dung count that only five of the 16 blocks showed evidence of
recent elephant activity.
Through boli measurements we were able to determine that the population consisted of
40 adults,
31 sub- or young adults, 21 juveniles and 10 elephants
of an age we couldn't determine because we didn't have boli circumference measurements.
Our samples for genetic testing, meanwhile, were preserved in a buffer
and stored at room temperature until they could be brought to the lab.
Once they reached Columbia,
we extracted DNA from each one and genotyped it,
which involves
creating a genetic profile for the elephant that left the dung.
Since each individual has a unique genotype, we were able to analyze our results
to determine the number of individuals we encountered
or "captured"
as well as the number of times we encountered them again
or "recaptured" them.
From the DNA analysis we learned that we'd collected samples from 102
individuals and that this group contained 79 females
and 29 males. Analysis of the capture and recapture history of those
individuals suggested that there were approximately 132 elephants
in the whole population.
There was a high level of genetic diversity in this group
with the highest diversity in blocks nine and ten
which were in the center.
We also determined that females and young
appeared to represent traditional family groups and that males tended not to be
related to female groups, which suggests that they may move into the area from
more than one location
mixing populations to avoid inbreeding between close relatives.
So when we combine the data
what does all this mean?
We were able to report that this population is genetically robust
and not in immediate danger of heavy inbreeding,
it's important to conserve because it is perhaps the largest population of Asian
elephants in Laos,
that it's likely to be part of a larger meta- population since the genetic diversity
level is relatively high
and the social structure is similar to that of a larger populations elsewhere
and that it's likely
that these elephants will move as relatively large family groups in search
of new habitat
if their current habitat is lost.
The dam was built and began operating in March, 2010,
and studies are underway to understand its actual effects on the elephants and
other wildlife species.
In this and in most of the work that we do,
the goal is not to make specific recommendations about the management
this population. Our job was simply to provide a foundation of data
on which decisions can be made by others.
In this way we hope to make a difference not only for the reclusive and dangerous
animals living in remote locations like Laos but also for animals residing
closer to home, such as Missouri's black bears and river otters.