Molecular Techniques and Conservation Biology

By Julie Pederson, Ph.D., and Neal Cosby, Ph.D.
Promega Corporation

There are 4 pages to this Feature:
Overview - Goals - Technology - Photos & References

Editor's Note: This Feature is offered as a supplement to the Applications article, Screening of the Gamµ-7 Microsatellite Locus to Determine the Sex of Captive Whooping Cranes. The goal of the Feature section of eNotes is to place a specific application in the context of science and research affecting all of us.

Composite image composed of (clockwise, from upper left) a whooping crane, STR sequencing gel results, DNA forensics studies and agarose gel analysis of PCR products. The photographs are linked by a cartoon representation of the PCR process, illustrated by a single cycle of amplification and including template DNA, oligonucleotide primers, thermostable DNA polymerase and nucleotides. Image of the whooping crane courtesy of the International Crane Foundation.

Overview

"As for other areas of molecular biotechnology, conservation genetics is an applied science with the important goal of describing explicitly the composite genomes of small endangered populations" (1).
--Stephen J. O'Brien

Analyzing DNA is common enough these days but for the most part the techniques are applied to readily available samples. The case for threatened or endangered animals, captive or in the wild, is much different. Extracting a tissue sample, much less locating or being granted access to such animals, presents real problems before applying molecular techniques. This story focuses on some of the current molecular techniques being applied in conservation biology.

Threatened species are those having an uncertain chance of continued survival, and likely to become an endangered species. Endangered species are those 'threatened' with extinction. These may not be the legally-binding definitions, but each conveys the meaning of the species being challenged in the face of a dwindling habitat ("threatened") versus the species consisting of only a few extant breeding individuals ("endangered"). Species are removed from the lists by one of two main ways: they recover or become extinct. For more information on threatened and endangered animals, see the U.S. Fish and Wildlife Service web site.

Name the threatened or endangered species and molecular techniques are more than likely being applied. For example, scientists in the genetics laboratory at the Brookfield Zoo in Illinois are collaborating on projects using i) PCR amplification, mtDNA sequence and enzymatic restriction to determine gender of monomorphic birds, such as the Humboldt penguin (endangered); ii) determine the species and subspecies of three genera of captive New World primates, owl monkeys (Aotus), spider monkeys (Ateles) and squirrel monkeys (Saimiri) distributed throughout Central and South America; iii) microsatellite loci and DNA fingerprinting methods for paternity analysis in gorillas and dolphins; and in studies on African wild lions, iv) PCR amplification, sequencing of cytochrome b and NADH dehydrogenase 5 genes, microsatellite analysis and DNA fingerprinting; v) multi-locus DNA fingerprint methods were used to determine that offspring born to a captive female Arafuran Filesnake at Brookfield Zoo had no father---apparently females can reproduce by parthenogenesis; vi) mtDNA sequence of both NADH dehydrogenase 5 and 6 subunits and cytochrome b were used to study the mountain brushtail possum in Australia. And this just from the files of a single institution. For an explanation of these and other techniques, see the Technology section of this article.

International Crane Foundation

The International Crane Foundation, or ICF, is one place where the current technology is aiding the 15 species of cranes, seven of which are endangered. The ICF was founded in 1973 by Ron Sauey and George Archibald, and has since concentrated efforts on recovering these populations of birds in five ways: research, education, habitat protection, captive breeding and restocking. The research efforts involve collaborations with scientists and conservationists in Europe, Asia, Australia and Africa, in addition to North America. Ken Jones, currently at the University of Chicago, is just one of many scientists who have traveled to Wisconsin to study cranes and apply current molecular techniques to the study of this species. Jones along with Travis Glenn of the Savannah River Ecology Laboratory in South Carolina, address the use of PCR for confirming sex in breeding pairs of whooping cranes in their article, Screening of the Gamµ-7 Microsatellite Locus to Determine the Sex of Captive Whooping Cranes.