Random Local Clock and Molecular Evolution Studies on Corydalis (Papaveraceae s. l.)

Molecular evolutionary rate and dating studies have been carried out on nuclear ribosomal DNA (nrDNA ITS I and II) and non-coding plastid DNA (rps16 intron) nucleotide sequences from Corydalis and other related genera in the poppy family Papaveraceae s. l. Strict, relaxed, and local clock models have been compared. Although it has been suggested that the nrDNA ITS I and II regions evolved in concert, they may have evolved at different evolutionary rates under differential constraints. Based on random local clock and uncorrelated relaxed lognormal clock Bayesian analyses using BEAST v.1.6.2, the ITS II region may have evolved in a clock-like fashion.