In Nature this week, researchers from the Dana-Farber Cancer Institute report animal data showing that small subgroups of tumor cells can drive proliferation of surrounding cancer cells. While it has long been known that tumors consist of different populations of cancerous cells with substantial genetic heterogeneity, just how this affects disease progression has been unclear. The scientists showed that tumor growth can be accelerated by a minor cell subpopulation, which enhances proliferation of all cells within a tumor but can be outcompeted by faster proliferating competitors, resulting in tumor collapse. They also described a mathematical model to identify the rules governing this relationship, which may help in the development of new cancer diagnostics and therapeutics.
Meanwhile, in Nature Genetics, a University of Arizona-led team report on the genome sequence of African rice, Oryza glaberrima, which is a completely different variety that the better-known Asian species. African rice is better suited to surviving in harsh environmental conditions, but the basis for such adaptations has been unclear. The plant's genome reveals that it was domesticated from a wild species about 3,000 years ago, and indicates that ancient farmers specifically, though unintentionally selected for genes that affect traits in both Asian and African rice, including reduced seed shattering and increased yield.
Also in Nature Genetics, a group of scientists led by Alisdair Fernie from the Max Planck Institute of Molecular Plant Physiology publish the genome sequence of the wild tomato species Solanum pennellii, an inedible species from South America that is currently used to improve key traits in the edible species. The investigators found genes related to dehydration resistance, fruit development, and fruit ripening, as well as ones that contribute to the higher levels of volatile compounds in the wild species that improve fruit scent and flavor. The results offer new insights into those genes that contribute to agriculturally useful traits.