[ExI] Discovery Suggests All Complex Life Came From Archaea

[BillK]

February 16, 2017 - 06:15

Scientists have discovered what could be our closest living relative
among the microbes, casting new light on the origins of our species.

<http://sciencenordic.com/discovery-bay-aarhus-can-solve-puzzle-our-primordial-origin>

Quote:

Life on Earth started at least 3.8 billion years ago, and nobody knows
how it started or why. But we do know that all life on Earth
originated from a single original cell.

Scientists thought that this cell eventually divided into three main
domains: two simple, small life forms called bacteria and archaea, and
one higher, more complex form, called eukaryotes.

But a new picture has emerged in recent decades that eukaryotes did
not originate as an independent line from the shared ancestor, but by
a combination of two cells from archaea and bacteria.

The leading scenario is that the two microbes evolved in such a way
that they became increasingly dependent on each other, eventually
combining in a complete symbiosis, as the archaeon took up the
bacterium.

By comparing the genetic material from many different organisms, the
scientists can see how the Asgard-group fit into the five or six major
groups of archaea.

Excitingly, eukaryotes follow a line of descent from the Asgard group.
>From blue whale to yeast, and to humans, we are all basically Asgard
archaea, which originated about two billion years ago.

“One could say that all we are is Asgard archaea with a mitochondrial
booster,” says Ettema.
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BillK