A massive analysis of 23,000 sets of genes representing most genera of plants has produced what the New York Times calls a makeover for the tree of life. They used the genomes from 150 plants but used supercomputers to identify groups of genes to compare. The seed-bearing plants go back 300 million years, to cycads and conifers, which are gymnosperms–plants with naked seeds unprotected by tough coatings. Those with protected seeds are called angiosperms.
The computer flagged certain proteins as having special significance for the functioning of plants, which could be the keys to important evolutionary relationships. Of the hundreds identified, the scientists randomly selected a few for testing, which confirmed their hunch that those proteins were responsible for plants’ following different evolutionary roads. Some of these relationships date back 300 million years, when the first gymnosperms, the group that includes pines and ginkgos, appeared.
Among other things, they’ve solved the position of gnetophytes.
The scientists organized the results into a phylogenomic tree according to their evolutionary interrelatedness, which included some surprising insights. For example, gnetophytes, a group that consists of shrubs and woody vines, are the most primitive nonflowering seed plants, according to the researchers’ analysis. Those plants date back to the Mesozoic “age of the dinosaurs” and form the base of the evolutionary tree of seed plants.
Here is one of the phylogenetic trees that resulted from this massive re-analysis: