Systematic Biology Publishes a Paper Finished by Researchers Mainly from SCBG

The paper “Resolving an Ancient, Rapid Radiation in Saxifragales” finished by Shuguang Jian from South China Botanical Garden, the Chinese Academy of Sciences, and others was published by the internationally prestigious journal, Systematic Biology in February 2008 (57: 38-57). This paper was the main achievements of Dr. Jian when he worked as a postdoctoral research fellow, in Soltis lab, Florida University, USA (2005-2006).

Saxifragales are one of several examples of angiosperm clades whose deep-level relationships have been difficult to resolve due apparently to a rapid, ancient radiation. The composition of Saxifragales is one of the major surprises of molecular phylogenetic studies of angiosperms. Saxifragales (sensu APG II, 2003) include Altingiaceae, Cercidiphyllaceae, Crassulaceae, Daphniphyllaceae, Grossulariaceae,Haloragaceae sensu lato (expanded to include Tetracarpaeaceae, Penthoraceae, and Aphanopetalum), Hamamelidaceae, Iteaceae, Paeoniaceae, Pterostemonaceae, Saxifragaceae, and Peridiscaceae. These families were placed in three or four different subclasses, Hamamelidae, Rosidae, Dilleniidae, or Magnoliidae based on the previous morphology-based classifications (e.g., Cronquist, 1981; Takhtajan, 1997; Morgan and Soltis, 1993). In this paper, use of ~ 50,000 bp (including two nuclear, four mitochondrial, ten plastid, and the entire plastid inverted repeat), deep relationships in Saxifragales can be resolved. Age estimates indicate that the early diversification of Saxifragales occurred rapidly, over a timespan as short as 6 million years. Extrapolating from Saxifragales, a similar number of base pairs may be needed to resolve the many other deep-level radiations of comparable age in angiosperms.