Archaea – a microbial cockatrice?
A cockatrice was a flamboyant sight at medieval banquets, featuring a roasted chimera of rooster fused to a suckling pig. In this article in Microbiology Today (pdf) Ed Bolt and Stephane Delmas suggest that there are similarities with archaea, ancient micro-organisms that have features of both bacteria and eukaryotes within their genomes:
Archaea and bacteria are micro-organisms that are similar, yet different. Archaea are evolutionarily ancient organisms that have soaked up diverse ecosystems for at least 2.5 billion years. They are, like bacteria, unencumbered by various complex sub-cellular structures (e.g. mitochondria, a membrane-bound nucleus) and as such have been for most of their long existence, or at least from when microbiologists started looking at them, considered to be bacteria that had evolved to thrive in extreme environments (e.g. at high temperature or salinity). For this reason they were often called archeabacteria. However, DNA sequencing experiments in the 1970s drove a wedge through the bacteria, splitting it into two separate domains of cellular life: the Bacteria and the Archaea. The genetic distinction between bacteria and archaea is now generally accepted since its original proposal in 1977, but has its evolutionary root much earlier, probably pre-dating the emergence of oxygen 2.5 billion years ago. Therefore, the classification of cellular organisms is now usually represented in a tree of life consisting of three domains, Bacteria, Archaea and Eukarya.
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Tags: Archaea, Bacteria, Biology, evolution, Microbiology, Science
