Non-invasive DNA analyses involve DNA collected without capturing or usually even touching an animal. It means collecting DNA from items that animals leave behind, including feces (scat, dung), hair, feathers, saliva, or shed skin. These items aren’t the same as more traditional and richer sources of DNA (blood, tissue), and DNA yield and quality tend to be lower. So, scientists have to be very careful in the handling, DNA isolation methods, and subsequent analysis of non-invasive samples.
Standard DNA methods, such as mitochondrial and nuclear DNA sequencing, microsatellite analyses, sex identification, and pathogen diagnosis, can be applied to these samples. The microsatellite and mitochondrial DNA markers are usually variable enough such that individuals (except for identical twins) can be identified from use of only a few markers. The non-invasive DNA approach is extremely useful for estimating population sizes and densities of species that might otherwise be difficult to detect and count.
Besides helping conservationists find and count endangered species, these genetic methods can help identify appropriate conservation and management units, and provide data on an individual animal's sex, movements, mating patterns, and relatedness to other individuals. The benefits of this approach include eliminating the need to observe, capture, and handle individuals.
CCEG’s program is one of only a few in the world with the necessary field and laboratory expertise to do this, and our scientists have conducted extensive studies on San Joaquin kit foxes, African wild dogs, maned wolves, coyotes, Assateague Island wild horses, tigers, and African elephants, among other species.
|CCEG non-invasively monitors African elephant populations through their dung and uses this information to determine their kinship for studies of inbreeding and behavior.
Photo credits: Beth Archie (elephants) and Marissa Ahlering (dung).