February 22, 2001

1 min read

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Leprosy's Little Genome

By Kate Wong

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Every year leprosy strikes nearly 700,000 people, causing devastating nerve damage, sensory loss and disfiguration. But a new analysis of the leprosy bacterium's genome, published today in the journal Nature, is providing fresh insight into the microbe's mysterious ways. The results could eventually lead to better ways for diagnosing and treating the disease.

Stephen T. Cole of the Pasteur Institute in Paris and his colleagues compared the gene sequence of the leprosy bacterium, Mycobacterium leprae, with that of the tuberculosis bacterium, M. tuberculosis, a close relative. Intriguingly, they found that M. leprae has undergone a major reductive evolution. That is, it has lost a large number of genes--so many, in fact, that it now has only the bare minimum necessary for survival. Because many of the lost genes were involved in metabolism, the organism divides slowly, which, combined with the fact that its nutrient requirements continue to elude researchers, has made growing it in the lab quite difficult. But with relatively few genes to wade through, scientists will now have an easier time identifying the important ones.

Knowing M. leprae's sequence should help researchers to identify molecular drug targets--products of the remaining few genes involved in metabolism, for example--as well as proteins that could enable the development of new diagnostic tests for the disease. The new study may likewise benefit efforts to develop novel drugs and vaccines for tuberculosis

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

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