An Irish scientist is helping to save the African cheetah from extinction by using DNA profiling, writes Courtenay Norbury
Cheetahs are perilously close to extinction, with only 12,500 cheetahs left in the world. A University of Ulster researcher is helping to tackle this problem by assisting conservationists in Namibia, the "cheetah capital of the world", to use DNA profiling as a way to enable cheetahs to meet more genetically diverse mates.
Dr Anne Bridgen, a lecturer in bioimaging, has just returned from a two-week stint as a volunteer worker at the Cheetah Conservation Fund International Research and Education Centre in Otjiwarongo, northern Namibia.
The visit was organised and funded by EarthWatch.
Dr Bridgen embarked on this adventure to investigate the possibility of establishing future collaborations between the University of Ulster and the Otjiwaronjo centre.
Current conservation efforts are hampered by the fact that cheetahs exhibit much lower levels of genetic variation than other mammals. About 10,000 years ago, cheetahs were close to extinction and their numbers dwindled. As a result, inbreeding was common and today's cheetahs are descended from a small number of ancestors.
"Lack of genetic variation is a problem because the animals have lower sperm counts and are more susceptible to disease," explains Dr Bridgen.
To address this problem, DNA samples are taken and analysed from cheetahs that are brought to the centre by neighbouring farmers.
The team look for microsatellites in the DNA, which Dr Bridgen describes as small repeated sequences of genetic material. Microsatellites have high mutation rates and are therefore valuable for showing genetic variation within a species.
"The DNA analysis enables researchers to determine how big the gene pool is," says Dr Bridgen.
At the moment, the centre is able to test DNA samples only in captive animals, but to maximise genetic diversity, it is important to determine the genetic make-up of cheetahs in the wild.
To do this, the research team covers trees with a special wire matting and sprays it with an animal scent to attract the cheetahs. As the cheetahs pass by the trees, hairs become trapped on the wire mat.
DNA can then be extracted from the samples of hair cells. Knowing the genetic make-up of cheetah populations in different geographical regions will assist the team in deciding where to release the captive animals so that they may encounter more genetically diverse cheetahs for mating.
During her two-week visit, Dr Bridgen says she was involved "in every facet of the programme going on there, from proof-reading papers for publication to advising on the equipment needed to carry out the DNA testing".
She is keen to develop future collaborations with the centre. "I was surprised by how much rabies there is in the area, particularly in the African antelope 'kudu'," Dr Bridgen reports.
This is a further challenge to conservation efforts as cheetahs eat the kudu and then become infected with rabies themselves.
"I would be particularly interested in working with the centre to develop a useful rabies vaccine for the cheetah," Dr Bridgen says.
About 12,500 cheetahs remain in 25 African countries, and only 100-200 cats survive in Iran, according to figures published by the Cheetah Conservation Fund. Namibia has the world's largest number, yet only 2,500 remain in the wild.
• For further information on the Otjiwarongo centre, see www.cheetah.org
• Dr Courtenay Norbury is a experimental psychologist at Oxford University and a participant in the British Association for the Advancement of Science Media Fellow Programme.