Call of the squash

Last fall, Thomas Andres was wandering around New York City's Chinatown when he happened upon the subject of his doctoral dissertation: the lacayote, Cucurbita ficifolia, a South American squash rarely sold in the United States. He was happy to shell out $6 for the mottled green gourd. Twenty-five years ago, he had dreamed of discovering its wild ancestor on some scrubby hillside in Mexico. Because centuries of inbreeding have reduced the genetic diversity of many domesticated crops, finding their natural populations could help scientists identify beneficial genes which could eventually improve crop lines. Unfortunately, the lacayote's wild ancestor never turned up, and Andres never quite finished his PhD.