SCIENTISTS studying the origins of life say some genes that shaped modern biology are older than the earliest common ancestor shared by all living organisms.
That ancestor, known as the last universal common ancestor, lived about four billion years ago and is the most ancient organism that can be examined using established evolutionary methods.
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Evidence shows that by this stage, cells already had membranes and stored genetic information in DNA, indicating that core biological systems were already in place.
Researchers therefore, argue that understanding how life first emerged requires probing evolutionary processes that occurred even earlier.
In a study published in the journal
Cell Genomics, Aaron Goldman of Oberlin College, Greg Fournier of the Massachusetts Institute of Technology, and Betül Kaçar of the University of Wisconsin–Madison describe a method to explore this deeper evolutionary past.
Goldman said that although the last universal common ancestor is the earliest organism accessible to study, some of its genes originated long before it existed.
The researchers focused on rare gene families known as universal paralogs, which occur in multiple copies across nearly all living organisms and are believed to have formed before the common ancestor emerged.
Their review found that every known universal paralog is involved in either protein production or the transport of molecules across cell membranes, pointing to these processes as among the earliest biological functions to evolve.
