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3) It is now possible to gather bear population data more efficiently through less intrusive conservation methods.For examples, DNA extracted from bear hair samples that are systematically collected from hair trap scan be used to identify an individual, its species, and gender without interacting directly with the bear.Each DNA fingerprint consists of a unique pattern of bands made visible in a gel through laboratory techniques. To estimate the number,
N,of bears in a area, a so-called mark and recapture method can be used.At first, a number of bear hair samples are collected T,and the bears these samples came from are identified through DNA fingerprinting technology. These bears are now tagged or marked.Two weeks later, another set of bear hair samples,S1,of bear hairs is collected in the same area, andthe new samples are analyzed. The number,St1, of tagged or previously identified bears in this second sample, is also counted.
N is the unknown total number of bears in this area. The proportion of identified or tagged bears in the total population should be approximately equal to the proportion of identified bears (St1) in the sample(S1).Therefore:
T/N=St1/S1
Since
T, S1, and St1
are known,
N
can be estimated by solving the equation.
N= ( TxS1)/St1
When the next set of bear hair samples, S2,is collected,
the bear’s identified in the previous bear hair samples have to be added to the initial number T
, or tagged , or identified bears, which is equal to
{( T +( S1-St1)}, to obtain the total number of bears that are now tagged or identified.
4) DNA probes
DNA probes are used to identify unknown samples of DNA and to find the base sequence of DNA.
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