ESTIMATION OF THE MONOCOT DICOT AGE THROUGH TRANSFER-RNA SEQUENCES FROM THE CHLOROPLAST

Using chloroplast tRNA sequences and evidence of absolute time estimates of splits within plant evolution, we were able to calculate the monocot-dicot divergence to be somewhere between 230 to 350 Ma before present (BP). The whole group of angiosperms must be older than this date. In rough agreement with previous studies, molecular data predate the appearance of angiosperms within the fossil record of about 100 to 200 Ma. We discuss implications of these molecular time estimates on the evolutionary interpretation of the morphological key innovations in angiosperms.