Summarizing Perspectives On the Phylogenetic Tree

Summary

The phylogenetic tree, first used by Darwin, is the classic “tree of life” model describing phylogenetic relationships among species, and the most common model used today. New ideas about HGT and genome fusion have caused some to suggest revising the model to resemble webs or rings.

Glossary

eukaryote-first hypothesis

proposal that prokaryotes evolved from eukaryotes

gene transfer agent (GTA)

bacteriophage-like particle that transfers random genomic segments from one species of prokaryote to another

genome fusion

fusion of two prokaryotic genomes, presumably by endosymbiosis

horizontal gene transfer (HGT)

(also, lateral gene transfer) transfer of genes between unrelated species

mitochondria-first hypothesis

proposal that prokaryotes acquired a mitochondrion first, followed by nuclear development

nucleus-first hypothesis

proposal that prokaryotes acquired a nucleus first, and then the mitochondrion

ring of life

phylogenetic model where all three domains of life evolved from a pool of primitive prokaryotes

web of life

phylogenetic model that attempts to incorporate the effects of horizontal gene transfer on evolution