Very recommendable! Amazing stuff! Great phylogenetics research!
"Around 2.5 billion years ago, our planet experienced what was possibly the greatest change in its history: According to the geological record, molecular oxygen suddenly went from nonexistent to becoming freely available everywhere. ...
The question that has not been resolved, however, is: Did the production of oxygen coincide with the GOE [Great Oxygenation Event], or did living organisms have access to oxygen even before that event? ...
o begin the study, Jabłońska sorted through around 130 known families of enzymes that either make or use oxygen in bacteria and archaea – the sorts of life forms that would have been around in the Archean Eon (the period between the emergence of life, ca. 4 billion years ago, and the GOE). From these she selected around half, in which oxygen-using or -emitting activity was found in most or all of the family members and seemed to be the founding function. That is, the very first family member would have emerged as an oxygen enzyme. From these, she selected 36 whose evolutionary history could be traced conclusively. ...
The phylogenetic trees the researchers ultimately obtained showed a burst of oxygen-based enzyme evolution about 3 billion years ago – something like half a billion years before the GOE. ..."
The question that has not been resolved, however, is: Did the production of oxygen coincide with the GOE [Great Oxygenation Event], or did living organisms have access to oxygen even before that event? ...
o begin the study, Jabłońska sorted through around 130 known families of enzymes that either make or use oxygen in bacteria and archaea – the sorts of life forms that would have been around in the Archean Eon (the period between the emergence of life, ca. 4 billion years ago, and the GOE). From these she selected around half, in which oxygen-using or -emitting activity was found in most or all of the family members and seemed to be the founding function. That is, the very first family member would have emerged as an oxygen enzyme. From these, she selected 36 whose evolutionary history could be traced conclusively. ...
The phylogenetic trees the researchers ultimately obtained showed a burst of oxygen-based enzyme evolution about 3 billion years ago – something like half a billion years before the GOE. ..."
"... However, the degree to which oxygen was available to life before oxygenation of the atmosphere remains unknown. Here, phylogenetic analysis of all known oxygen-utilizing and -producing enzymes (O2-enzymes) indicates that oxygen became widely available to living organisms well before the Great Oxidation Event. About 60% of the O2-enzyme families whose birth can be dated appear to have emerged at the separation of terrestrial and marine bacteria (22 families, compared to two families assigned to the last universal common ancestor). This node, dubbed the last universal oxygen ancestor, coincides with a burst of emergence of both oxygenases and other oxidoreductases, thus suggesting a wider availability of oxygen around 3.1 Ga. [Gigaannum 10^9]"
Here is the link to the referenced paper:
The researchers at the coffee table with pencil and notebooks (almost quaint)? 😄
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