[meteorite-list] Astrobiologists Find Martian Clay Contains Chemical Implicated in the Origin of Life

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 11 Jun 2013 10:13:52 -0700 (PDT)
Message-ID: <201306111713.r5BHDqHs007868_at_zagami.jpl.nasa.gov>

http://www.ifa.hawaii.edu/info/press-releases/MartianClay/

UH Astrobiologists Find Martian Clay Contains Chemical Implicated in the Origin of Life
University of Hawaii
For immediate release
June 10, 2013

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
<http://www.plosone.org/article/info%3Adoi/10.1371/journal.pone.0064624>.

The Antarctic Search for Meteorites team found the Martian meteorite
used in this study in Antarctica during its 2009-2010 field season. The
minerals it contains, as well as its chemical composition, 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
RNA molecules 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 early Earth 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 evolutionary
biologist, and Lydia Hallis, a cosmochemist who is also a UHNAI
postdoctoral fellow, 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."

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 life's key molecular building blocks could form.

UHNAI is a research center that links the biological, chemical, geological,
and astronomical sciences to better understand the origin, history,
distribution, and role of water as it relates to life in the universe.

Contacts

Dr. James Stephenson
3jds54 at gmail.com

Ms. Louise Good
Media Contact
1-808-956-9403
lgood at hawaii.edu
Received on Tue 11 Jun 2013 01:13:52 PM PDT