DNA: A Key to Unlock the Secrets of an Elusive Cat
Originally published in Snow Leopard Tracks, Summer 2006
Advances in genetics have resulted in a valuable new technique to estimate snow leopard populations. This is done by analyzing the DNA from samples of wild snow leopard scat and shed hairs that are collected in the field.
The Trust has been working with Dr. Lisette Waits of the Laboratory for Ecological and Conservation Genetics at the University of Idaho to apply this technique to snow leopards. Her lab analyzed 85 samples of wild snow leopard scat collected as part of recent Trust-sponsored projects in China and the Kyrgyz Republic. Recently, Dr. Waits took some time out to answer our questions about how this cutting-edge science works.
How does genetic analysis help answer questions about snow leopard populations?
First, it helps determine the presence or absence of snow leopards in a particular area. Second, it enables us to identify individual snow leopards, and as a result get a count of the snow leopards in that area. Finally, it helps answer broader questions about snow leopard populations, including the genetic health and diversity, and the migration and breeding patterns of populations.
How is snow leopard DNA different from human DNA?
There is a smaller difference than you might expect. Less than 15% of the snow leopard’s DNA differs from that of humans. This is why many of the human genetic analysis techniques that have been developed in recent years can also be applied to analyze snow leopards and other species.
DNA from domestic cats is even closer to snow leopards. So in addition to techniques used in human DNA analysis, data from the Feline Genome project at the Laboratory of Genomic Diversity at the National Cancer Institute has been extremely helpful in our genetic analysis of snow leopards.
Are there differences in testing snow leopard samples versus other species you study?
Basically we use the same lab protocols testing snow leopard samples as we do for other carnivore species. But since there is less genetic diversity in snow leopard populations, it is more challenging to identify individual snow leopards from the genetic material.
Is it possible to test snow leopard hair?
Yes, it is definitely possible to test shed snow leopard hairs. But for the current project we are only working with scat samples. At my lab we have done DNA analysis on hairs from a variety of species, including several species of bears. In addition to hairs, we have even been able to analyze DNA from molted parrot feathers. Scat contains much less DNA material than a genetic sample of multiple hairs hairs. But, it is much easier to find snow leopard scat samples than hair samples.
What is the progress on the current snow leopard samples at your lab?
So far we have extracted the DNA from the snow leopard scat samples we have, and have done a first screen of 20 samples using a species identification test. The point of the test is to confirm which samples are truly from snow leopards, and those we will be able to use for additional testing, such as identifying individual snow leopards. We have been able to amplify DNA and determine the species from 100% of these initial samples, which is a promising result. In this group of 20 scats, we found 12 snow leopards, plus foxes, martens, and one wolf. After completing species identification on all scats, the snow leopard samples will be analyzed to determine how many unique individuals were sampled.
Did You Know?
Believe it or not, enzymes originally found in bacteria living in geysers in Yellowstone National Park play a key role in a broad range of DNA analysis being done today in medical and biological labs around the world. This analysis includes diagnosis of infectious diseases, genetic fingerprinting used in crime investigations, analyzing DNA from extinct species—and the work Dr. Waits is doing on snow leopards. The enzymes are used as part of a scientific technique called the PCR (polymerase chain reaction) method. In a nutshell, PCR enables scientists to amplify or copy a small amount of DNA in a test tube to create thousands or millions of copies. So the method is invaluable when the scientist has access to only a small amount of original DNA material. In 1993, Dr. Kary Mullis, who invented the PCR method, was awarded the Nobel Prize in Chemistry.