Bacterium breaks all the rules. Cell structured like animal.
|March 27, 2017||Posted by News under Cell biology, News|
From Jennifer Frazer at Scientific American:
Gemmata obscuriglobis excels at breaking rules. Like the platypus, to whom these bacteria have been compared, they possess a baffling arsenal of oddities.
Although it has been controversial, they seem to contain membrane-bound compartments. One of those compartments surrounds their DNA. That would make it, apparently, a nucleus. But bacteria are thought to be devoid of nuclei – hence the terms prokaryote (“pre-kernel”) for bacteria and archaea, and eukaryote (“true kernel”) for all nucleated life (which includes all multicellular organisms).
The eye-popping apparent commonalities don’t end there.
If that is the case, it means one of two equally astounding things must be true: either this humble bacterium, isolated from freshwater near the Maroon Dam in Queensland, Australia is the closest living relative of eukaryotes, and split from our last common ancestor with bacteria long ago. Or it has independently evolved, under similar pressures, shockingly similar solutions to the same cellular and biochemical problems, right down to the architecture of its nuclear pores. More.
Well, if Gemmata obscuriglobis is the closest living ancestor of eukaryotes, it’s odd that no one had thought so before. If not, this is a dramatic example of convergent evolution.
What the world needs now is a dose of good old-fashioned there-is-no-debate Darwinian fundamentalism, to resolve this stuff.
See also: Evolution appears to converge on goals—but in Darwinian terms, is that possible?
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