Ah, what a life for silkworms at the University of Rhode Island. And what a metamorphosis -- from tiny, brown worms munching on mulberry leaves to a yellow cocoon made of a single thread 1,500 yards long to moths sprouting creamy white wings tinged with brown.
All under the watchful eyes of University of Rhode Island molecular geneticist Marian Goldsmith who probably knows more about what makes them crawl, spin, and flap than most people in the world. Goldsmith doesn't keep her lepidopteran knowledge to herself, but willingly shares her vast understanding of the silkworm with scientists worldwide.
In fact, the Kingston resident, a professor in URI's Biological Sciences Department located in the College of Arts and Sciences, recently was awarded a gold medal for her work. The Japan Society of Sericultural Science bestowed its highest honor -- a gold medallion -- upon Goldsmith for her Olympian knowledge of the silkworm or Bombyx mori. Only two such awards are given each year, never to an American. Goldsmith is the first woman to be so honored.
"Thousands of scientists have studied fruit flies because of their genetics," explained the URI professor, "but I chose the silkworm in the pre-genomics era because its much larger size made it such a good genetic model for isolating genes and studying how they work."
Goldsmith's not interested in the creation of better silk for the fashion industry, but is leading the research in genetic mapping of silkworms. It's a formidable task. The silkworm genome is a sixth the size of the human genome. Goldsmith is looking at where the genes are and what they are doing.
She is involved in an informal collaboration with Japan and India to construct a molecular linkage map. Such studies can lead to a deeper understanding of the evolutionary and selective forces that contributed to the silkworm's domestication and help unravel the selective forces in nature which promote evolution and change among wild species. Domesticated for the past 5000 years, silkworms live only in captivity and cannot survive independently in nature, particularly since they have lost their ability to find food and fly.
To study genetic traits, Goldsmith has studies underway to map genes controlling cocoon shell weight -- a measure of silk yield--and pupal body size which strongly influences both silk and egg production.
The URI professor's work does have a practical application to the agricultural industry. The silkworm larva is an ideal model for agricultural pests where there is little information available. Goldsmith is looking at the genetics of resistance to an insecticidal protein, Bt. Produced by a soil bacterium, Bt has enjoyed a great field record against caterpillars for the past three decades. However, one pest has become resistant to the insecticide in the field and many more now are being exposed to it in genetically engineered crop plants. Will more species start to develop resistance?
Because of its easy handling and well-developed genetics, the silkworm should be an effective model for uncovering genetically based mechanisms of resistance and the study of the genes involved. Practical outcomes of the Bt studies may include new diagnostic tools for resistance, improved toxin design, and breeding Bt-resistant silkworms for commercial use.
Goldsmith's gold medal is a crowning achievement for her. Her collaborative work with Japan spans three decades, beginning with a trip there in 1972 as a postdoctoral fellow on a National Science Foundation grant.
Goldsmith also founded and continues to coordinate a weeklong conference that is held every three years in Crete. The conference draws scientists from around the world with talk of lepidopteran (the scientific name for butterflies and moths) knowledge.
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