It’s a Genomic Jungle Out There

Tropical biologists are beginning to use the same genetic-fingerprinting techniques to identify new species that CSI sleuths use to nab criminals. Among these techniques is the "polymerase chain reaction," or PCR technique, which enables scientists to use a DNA-copying enzyme to easily mass produce precise copies of tiny samples of DNA from organisms. Another major tool is the same powerful DNA sequencing technology that enabled sequencing of the human genome and other organisms. This technology enables scientists to rapidly deduce the telltale structure of these DNA molecules.

Such technologies can be applied to analyze insect parts, feathers, scales, toenail-clippings, and other minute tissue samples to pinpoint the genetic identity of an animal, said Pedro León, a tropical biologist, at the OTS 40th-anniversary symposium.

With social insects, which live in interdependent colonies, “this is quite nice, because you can sample a few animals without being concerned about major impact on the population,” said León, a University of Costa Rica professor and former chair of the OTS board of directors. This kind of data will enable researchers to identify how individual animals and plants are related to one another, and how they spread, he said.

The genetic data can also help organize the multitude of species on the phylogenetic tree of life by comparing genetic data among them.
Perhaps most dramatic, said León, will be the “shotgun approach” to genomic identification of organisms. Scientists can take a soil sample and isolate the DNA of a multitude of unknown species. By analyzing the genes contained in the DNA, eventually the scientists will be able to determine the identities of the unknown organisms.

Finally, to explore in detail the identity and biological machinery of a plant, animal or bacterium, researchers can use so called "gene chips" arrays of thousands of genes deposited as tiny spots on a fingernail-sized glass slide. The gene arrays can represent those specific to a tissue, a disease, or a species of animal. By isolating a mixture of genetic material from an animal and applying it to the chips, fluorescent markers can give a readout of which of the thousands of genes are switches on or off. The power and speed of such analyses will be stunning, says León "Some day we’ll be teaching courses where if you have any doubts about a bacterial species, you probably will solve it with a little microarray in a half hour," he says. Before such powerful techniques, such analyses might take months or even years.