In the last ten years, geneticists have found a variety of applications for DNA analysis ranging from identifying hereditary mutations to developing new therapeutic drugs. Now, researchers have used genetic analysis to help officials fight animal trafficking in West Africa. In a recent study, researchers from the University at Albany (Albany, NY, USA) and the Limbe Wildlife Center (Cameroon, Africa) analyzed the mitochondrial DNA (mtDNA) of chimpanzees from different locations in Nigeria and Cameroon to establish familial lines. This analysis allowed researchers to determine where the rescued chimpanzees originally lived before they were captured by poachers.
The researchers compared the sequences of 464 chimpanzees from the International Nucleotide Sequence Database (collected from 10 locations across Nigeria and Cameroon), 46 chimpanzees rescued by the Limbe Wildlife Center, and 86 additional chimpanzees from the 10 specific target locations.
The researchers identified two species of chimpanzee present among the samples, Pan troglodytes and Pan ellioti, which were separated into two major haplotypes. Haplotype 1 consisted of P. ellioti and was divided into two subgroups. Haplotype 1a included chimpanzees from western Nigeria, and haplotype 1b consisted of chimpanzees from eastern Nigeria and Cameroon. Haplotype 2 consisted of P. troglodytes and was divided into three subgroups, all of which were taken from sites in southern Cameroon.
The samples included DNA from whole blood and hair. The researchers assembled genotype profiles and then amplified the samples with PCR. Following amplification, each sample was analyzed on Applied Biosystems’ ABI 31.30 capillary array genetic analyzer. Fragment sizes and allele sizes were determined on Applied Biosystems’ Genescan 600 and Genemapper ID version 2.7, respectively.
To analyze the samples by location, the researchers used Bayesian approximation methods and microsatellite genotype information on the Smooth and Continuous AssignmenTs (SCAT) software platform, which was developed in the laboratory of Matthew Stephens in the Department of Genetics at the University of Chicago. SCAT uses allele frequencies from geo-referenced samples combined with spatial smoothing methods to generate a geographic map of allele frequency variation for the 10 target locations.
The study, led by Mary Katherine Gonder, assistant professor of biological sciences at the University at Albany, revealed that the chimpanzees in Haplotype 1b, from eastern Nigeria and Cameroon, included 32 of the 46 chimpanzee rescued from poachers by the Limbe Wildlife Center. The remaining rescued chimpanzees were from sites in Cameroon. "We found that the rescued chimps were from Cameroon, implying that international smuggling is less of a problem than local trade,” said Gonder in a press release. “Worryingly though, the problem seems to occur throughout Cameroon, with some rescued chimps even coming from protected areas.”
According to the press release, poverty in West Africa drives the animal trafficking market. But it’s peculiar that local smuggling appears to be more commonplace: a poacher can get up to $20,000 for a live chimpanzee on the international black market, but only $100 within Cameroon itself.
"Most of the chimpanzees at Limbe Wildlife Centre belong to the most endangered subspecies of chimpanzee,” said Gonder. “They only inhabit Nigeria and adjacent parts of Cameroon. In 2004, this subspecies was predicted to be extinct within the next 25 years if current rates of decline continue.”
According to the press release, chimps are often taken by poachers who are looking for other animals, many of which are also endangered. Researchers hope that by identifying these hunting patterns and smuggling routes, officials will be able to reduce instances of animal trafficking among other species, such as Loxodonta africana (African elephant).
The paper, “Tracing the origins of rescued chimpanzees reveals widespread chimpanzee hunting in Cameroon,” was published online Jan. 22 in BioMed Central’s open-access journal BMC Ecology.