Relative Time Inference Using Lateral Gene Transfers.

Many organisms are able to incorporate exogenous DNA into their genomes. This process, called lateral gene transfer (LGT), has the potential to benefit the recipient organism by providing useful coding sequences, such as antibiotic resistance genes or enzymes which expand the organism's metabolic niche. For evolutionary biologists, LGTs have often been considered a nuisance because they complicate the reconstruction of the underlying species tree that many analyses aim to recover. However, LGT events between distinct organisms harbor information on the relative divergence time of the donor and recipient lineages. As a result transfers provide a novel and as yet mostly unexplored source of information to determine the order of divergence of clades, with the potential for absolute dating if linked to the fossil record.