A team of British specialists in population ecology have made a breakthrough in the collection of rare data on some endangered animals by developing the technique of DNA fingerprinting
SCIENTISTS from the Natural Environment Resource Council (NERC'S),
Institute of Terrestrial Ecology at
Banchory, and the department of zoology at the University of Aberdeen -
both in Scotland - have embarked on a
novel method to study population ecology. The programme called Molecular
Genetics in Ecology (MGE) Initiative,
Uses DNA fingerprinting and has been in
operation since September, 1994. The
team is working towards developing
DNA markers known as microsatellite
primers that will help establish the animal's individual and group identity
(NERc news, No 34).
Population ecology is a field which
specialises in collecting data on individual animals, paying attention to such
details as their life expectancy, the number of offspring produced by them, their
habitat area and the causes of their
death. This exercise helps determine
whether or not a certain isolated population will survive in the face of
unfavourable conditions.
Certain groups of animals like birds
can be trapped easily and marked unobtrusively, and then re-captured or resighted to obtain the necessary information. But there are animals which are
difficult to catch and observe" making
population studies on them an awesome
task. Scientists hope to overcome these
problems by applying the DNA fingerprinting technique, so that each individual would have a unique identity.
Trace quantities Of DNA which can be
retrieved from the individual's hair,
feathers, egg membranes and even
droppings, would be sufficient to establish the animals' identity. Moreover, the
use of this technique does not call for
the capture of the animals. The team has
used the technique to study the population dynamics of otters, re@ -grouse,
water-voles and winter moths.
The Eurasian otter - a secretive
and endangered carnivore - is
extremely difficult to spot in the wild
and as difficult to capture. The MGE
team collected otter droppings
(spraints) and extracted reasonable
amounts Of DNA from it. If successful,
the researchers shall be able to track
the movement of individual otters
and trace their relation to others in the
local population.
Populations of the red grouse - a
common bird found in the British
moorlands - are known to fluctuate
every five to 12 years. The reasons for
these changes are attributed to the tendency of these creatures to inbreed, and
the harm caused by the parasites harboured by them. The degree of relatedness among the red grouse - which
normally prefer kin as neighbours and
mates - tend to
change as their population begins wavering.
The study has so far
focused only on a small
population of grouse.
Now the MGE team is
working towards developing primers specific
to the red grouse.
Water-vole populations in the UK are
rapidly declining. The
species' survival now
depends on the animal's ability to disperse and re-colonise. Dispersal on the basis of the sex of the
animal results in the males moving out
and the females staying back. The success of re-colonisation therefore,
depends on the movement of both sexes
to the new site. The'MGE initiative -
through mitochondrial DNA and
microsatellite markers - plans to study
the movements of the animals between
dispersed populations, and also discover
whether or not sex-specific dispersal
affects population viability. Such
knowledge will help in devising conservation- strategies for the water-voles.
The MGE initiative is also developing
DNA markers to differentiate between
the different types of winter moth which
feed on different plants. The moths are
known to share host-parasite relationships with broad-leaved trees like oak
and birch, but now their range seems to
have extended to other plants such as
the unpalatable Sitka spruce and
heather. Preliminary results indicate,
that different genetic types are associated
with different hosts, and that there is
lesser genetic variation within the group
feeding on heather and-Sitka spruce.
The work conducted through the
MGE initiative has proved significant not
only to study population dynamics of
species, but also to develop effective
conservation strategies to save these
animal populations.
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