Astrobiologists find Martian clay contains chemical implicated in the origin of life

Astrobiologists find Martian clay contains chemical implicated in the origin of life
Electron microscope image showing the 700-million-year-old Martian clay veins containing boron (100 µm = one tenth of a millimeter).

(Phys.org) —Researchers from the University of Hawaii at Manoa NASA Astrobiology Institute (UHNAI) have discovered high concentrations of boron in a Martian meteorite. When present in its oxidized form (borate), boron may have played a key role in the formation of RNA, one of the building blocks for life. The work was published on June 6 in PLOS One.

The Antarctic Search for Meteorites team found the used in this study in Antarctica during its 2009-2010 field season. The minerals it contains, as well as its , clearly show that it is of Martian origin.

Using the ion microprobe in the W. M. Keck Cosmochemistry Laboratory at UH, the team was able to analyze veins of Martian clay in the meteorite. After ruling out contamination from Earth, they determined boron abundances in these clays are over ten times higher than in any previously measured meteorite.

"Borates may have been important for the origin of life on Earth because they can stabilize ribose, a crucial component of RNA. In early life RNA is thought to have been the informational precursor to DNA," said James Stephenson, a UHNAI postdoctoral fellow.

RNA may have been the first molecule to store information and pass it on to the next generation, a mechanism crucial for evolution. Although life has now evolved a sophisticated mechanism to synthesize RNA, the first must have been made without such help. One of the most difficult steps in making RNA nonbiologically is the formation of the RNA sugar component, ribose. Previous laboratory tests have shown that without borate the chemicals available on the fail to build ribose. However, in the presence of borate, ribose is spontaneously produced and stabilized.

This work was born from the uniquely interdisciplinary environment of UHNAI. The lead authors on the paper, Stephenson, an , and Lydia Hallis, a cosmochemist who is also a UHNAI , first came up with the idea over an after-work beer. "Given that boron has been implicated in the emergence of life, I had assumed that it was well characterized in meteorites," said Stephenson. "Discussing this with Dr. Hallis, I found out that it was barely studied. I was shocked and excited. She then informed me that both the samples and the specialized machinery needed to analyze them were available at UH."

Astrobiologists find Martian clay contains chemical implicated in the origin of life
Thin section of the Martian meteorite MIL 090030 analyzed by the UHNAI researchers.

On our planet, borate-enriched salt, sediment and clay deposits are relatively common, but such deposits had never previously been found on an extraterrestrial body. This new research suggests that when life was getting started on Earth, borate could also have been concentrated in deposits on Mars.

The significance goes beyond an interest in the red planet, as Hallis explains: "Earth and Mars used to have much more in common than they do today. Over time, Mars has lost a lot of its atmosphere and surface water, but ancient meteorites preserve delicate clays from wetter periods in Mars' history. The Martian clay we studied is thought to be up to 700 million years old. The recycling of the Earth's crust via plate tectonics has left no evidence of clays this old on our planet; hence Martian clays could provide essential information regarding environmental conditions on the early Earth."

The presence of ancient borate-enriched clays on Mars implies that these clays may also have been present on the early Earth. Borate-enriched clays such as the ones studied here may have represented chemical havens in which one of 's key molecular building blocks could form.


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More information: Stephenson, J. D., Hallis, L. J., Nagashima K., and Freeland, S. J. 2013, "Boron Enrichment in Martian Clay," PLoS ONE 8(6): e64624. dx.doi.org/10.1371/journal.pone.0064624
Journal information: PLoS ONE

Citation: Astrobiologists find Martian clay contains chemical implicated in the origin of life (2013, June 11) retrieved 23 July 2019 from https://phys.org/news/2013-06-astrobiologists-martian-clay-chemical-implicated.html
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JVK
Jun 12, 2013
Is it reasonable to assume from its presence on Earth that one chemical in Martian clay enabled life to somehow adaptively evolve (e.g., via the nutrient-dependent pheromone-controlled ecological, social, neurogenic, and socio-cognitive niche construction, which allows people to make that assumption?) To me, that assumption seems rather simple-minded. Indeed, even this article states that "...life has now evolved a sophisticated mechanism to synthesize RNA..."

Is it wrong to think that the sophisticated molecular mechanisms of synthesized RNA did not come from outer space and randomly put themselves together to result in the alternative splicings of DNA we now know are responsible for adaptive evolution in species from microbes to man? Or have the astrobiologists simply concocted a story that fits the expectations of evolutionary theorists?

Jun 14, 2013
It is my personal opinion that Mars sustained life at some point, and may still in some as yet undiscovered locale. That said, however, I am please that our efforts on the Red Planet have paid off and eventually, may leave us to pin a medal on the Viking missions as well. Only time and effort will reveal the final answer... let's go to Mars!

Jun 14, 2013
Is it reasonable to assume from its presence on Earth that one chemical in Martian clay enabled life to somehow adaptively evolve (e.g., via the nutrient-dependent pheromone-controlled ecological, social, neurogenic, and socio-cognitive niche construction, which allows people to make that assumption?) To me, that assumption seems rather simple-minded
-And yet youre not cognitively developed enough to detect how full of potatoes you are. Try concentrating.

JVK
Jun 14, 2013
Try addressing the biological facts:

Kohl, JV (2013) Nutrient--dependent / pheromone--controlled adaptive evolution: a model
Socioaffective Neuroscience & Psychology, 3: 20553

http://dx.doi.org...i0.20553

Any fool can simply say Nuh-uh; our origins were on Mars.

Jun 14, 2013
Try addressing the biological facts:

Kohl, JV (2013) Nutrient--dependent / pheromone--controlled adaptive evolution: a model
Socioaffective Neuroscience & Psychology, 3: 20553

http://dx.doi.org...i0.20553

Any fool can simply say Nuh-uh; our origins were on Mars.


Any fool can simply misinterpret the article and thinks it says our origins were on Mars. But if ya have clay for brains, ya just might think this article has anything at all to with stinky hormones.

I bet ya are one of those un-"intelligent design" thinking "scientists", eh?

Jun 14, 2013
@JVK: Yes, it is reasonable that every mechanism that increases ease and complexity of chemical evolution enables later biological evolution. "in the presence of borate, ribose is spontaneously produced and stabilized."

Your Gish gallop on evolutionary mechanisms fails absurdly when you mention "socio-cognitive" such, as most life evolves without. In the same way that life started out simple, the mechanisms were fewer and less complex.

And similar to how biological evolution is not "random" but deterministic (selection) and contingent (mutation), chemical evolution is so too. As "in the presence of borate [chemical contingency], ribose is spontaneously produced and stabilized [chemical determinism]" tells us.

Jun 14, 2013
[ctd] In fact, we now know that thermodynamics crystallizes a "gas" of random strands (in solute) assembled from activated nucleotides (say, produced by alkaline hydrothermal vents) into a replicator in ~30 000 years.

This is no different from other crystals, who can grow and replicate as well, but has much less variability to couple to the environment with. Hence cells evolve biologically, crystals still evolve chemically.

Hence, according to physics, life _must_ appear in some of the environments we see (such as alkaline hydrothermal vents), given how replication* and vesicle formation** works.

* Replication in chemicals like RNA, that also can do other functions (enzymatic & structural).

** Which is not a spontaneous equilibrium process, or bubbles couldn't grow. But we all know it is darn near impossible _not_ to form bubbles out of lipids and similar chemicals combined with mechanic action such as waves.

JVK
Jun 14, 2013
~30,000 years is the time it took for a human population to adaptively evolve in what is now central China. I attribute the nutrient-dependent pheromone-controlled morphogenesis to the thermodynamics of epigenetically-effected intracellular changes that lead to internuclear interactions and the stochastic de novo gene expression required for species diversification via pheromone-controlled organism-level thermoregulation of reproduction.

Do you think the thermodynamics of gas crystallization in ~30,000 years is coincidental? I think that at least one physicist might want to look at it in the context of adaptive evolution that started with the first cell on this planet. Whether or not it had a socio-cognitive niche, ours had to come from somewhere. If its development involves chemicals from outside our atmosphere, then start with how they are important to biological evolution. Don't just tell biologists that a chemical might be important. Tell us HOW it is important!

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