Abstract
Reconstructing the phylogenetic relationships that unite all biological lineages (the tree of life) is a grand challenge of biology. However, the paucity of readily available homologous character data across disparately related lineages renders direct phylogenetic inference currently untenable. Our best recourse towards realizing the tree of life is therefore the synthesis of existing collective phylogenetic knowledge available from the wealth of published primary phylogenetic hypotheses, together with taxonomic hierarchy information for unsampled taxa. We combined phylogenetic and taxonomic data to produce a draft tree of life – the Open Tree of Life – containing 2.3 million tips. Realization of this draft tree required the assembly of two resources that should prove valuable to the community: 1) a novel comprehensive global reference taxonomy, and 2) a database of published phylogenetic trees mapped to this common taxonomy. Our open source framework facilitates community comment and contribution, enabling a continuously updatable tree when new phylogenetic and taxonomic data become digitally available. While data coverage and phylogenetic conflict across the Open Tree of Life illuminates significant gaps in both the underlying data available for phylogenetic reconstruction and the publication of trees as digital objects, the tree provides a compelling starting point from which we can continue to improve through community contributions. Having a comprehensive tree of life will fuel fundamental research on the nature of biological diversity, ultimately providing up-to-date phylogenies for downstream applications in comparative biology, ecology, conservation biology, climate change studies, agriculture, and genomics.
