The Scientist: Life on land half a billion years older than thought is a top 2018 story

_{Denyse O'Leary

December 28, 2018

Evolution, Intelligent Design, Origin Of Life}

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From a piece that didn’t number the stories, this one was second:

In July, scientists announced that they had uncovered the earliest evidence of terrestrial life on Earth. “This work represents the oldest and least ambiguous work that we have so far that life existed on land already 3.2 billion years ago,” Kurt Konhauser, a professor of earth and atmospheric sciences at the University of Alberta in Canada who was not involved in the work, wrote in an email to The Scientist. Kerry Grens, “he Biggest Science News of 2018” at The Scientist

The find, ancient microbes in South Africa, backdates terrestrial life by half a billion years, raising the obvious issues about the long, slow process that is supposed to have taken place.

See also: The Scientist: Oldest evidence of terrestrial life is half a billion years older than thought

and

See also: Soil micro-organisms older than thought

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Pavel- Please buy a vowel as Intelligent Design is NOT anti-evolution. Intelligent Design says that organisms were designed to evolve and adapt.ET_{December 30, 2018
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Here's another interesting paper that explains evolution: Separation and Loss of Centrioles From Primordidal Germ Cells To Mature Oocytes In The Mouse PDF
Mammalian oocytes lack centrioles, but how or at what stage mature eggs lose their centrioles during oogenesis is unknown.

In most mammals, haploid female gametes produced during oogenesis lose their centrosomes, although the mechanism of when and how remains elusive

predictions that molecular genetic approaches would answer definitively inheritance questions, following on the discovery of DNA in mitochondria (Nass and Nass, 1963; Margulis, 1970), failed.

[centrosomes and centrioles] assembly is tightly regulated and orchestrated

the question as to whether centrosomes and centrioles are inherited, strictly speaking, may need to be examined more stringently.

Centriole disassembly, studied here in oocytes during the last two meiotic divisions, remains challenging

The precise mechanism of CETN2 doublet separation is not currently known.

Investigations on the precise molecules essential for centriole persistence and PCM functionality in the doublets and their fates during oocyte growth and maturation to metaphase-II arrest await future studies.

Centriole destruction may be prerequisite for terminal differentiation, and the retention of centrioles is associated with proliferation, regeneration, pluripotency, perhaps even totipotency.

Perhaps the last phase of oogenesis (i.e., oocyte maturation) is another example of terminal differentiation, including with the elimination of centrioles and centrosomes. Interestingly, while it appears necessary to undergo two mitotic cycles to generate centrioles, perhaps during both spermatogenesis and oogenesis, the last two meiotic cycles also are prerequisite for centriole destruction.
PavelU_{December 30, 2018
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Here's another paper that explains evolution in details: Comparative Biology of Centrosomal Structures in Eukaryotes
The centrosome is not only the largest and most sophisticated protein complex within a eukaryotic cell, in the light of evolution, it is also one of its most ancient organelles.

The centrosome is a non-membranous, nucleus-associated organelle that functions as the main microtubule organizing center (MTOC) in many eukaryotes and thus, also as an organizer of the mitotic spindle. With a number of, in some cases, more than 100 different proteins and a size of more than 0.5 µm the centrosome is the largest and most elaborate protein complex in a eukaryotic cell.

the once mysterious organelle “centrosome” has disclosed many of its secrets, especially regarding its composition and microtubule organization. Still there are many open questions. How is the assembly of about a hundred different centrosomal components into a highly sophisticated topology regulated through various signaling pathways, how are centrioles/basal bodies involved in signaling at primary cilia, how are centrosomal proteins involved in the etiology of several devastating diseases and last not least, what is the evolutional relationship of centrosomes with nuclear pore complexes.
PavelU_{December 30, 2018
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To all ID folks: Here's another paper that explains evolution: Molecular and evolutionary strategies of meiotic cheating by selfish centromeres PDF ResearchGate
Identifying genes with signature of rapid evolution may provide further insights into how genomes have evolved to suppress drive, through either a weak checkpoint or other mechanisms. Our cell biological studies of centromere drive, combined with such molecular evolution analysis, will lead to a deeper understanding of the molecular arms race between selfish elements and the rest of the genome.
PavelU_{December 30, 2018
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