Biosignatures may reveal a wealth of new data locked inside old fossils


Date:
July 13, 2020
Source:
Yale University
Summary:
Step aside, skeletons -- a new world of biochemical ''signatures''
found in all kinds of ancient fossils is revealing itself to
paleontologists, providing a new avenue for insights into major
evolutionary questions.



FULL STORY ==========================================================================
Step aside, skeletons -- a new world of biochemical "signatures" found
in all kinds of ancient fossils is revealing itself to paleontologists, providing a new avenue for insights into major evolutionary questions.


==========================================================================
In a new study published in the journal Science Advances, Yale researchers outline a novel approach to finding biological signals long thought to
be lost in the process of fossilization. The new approach has already
yielded valuable information about the soft shells that encased the
first dinosaur eggs and shown that an ancient creature known as the
Tully Monster was a very unusual vertebrate.

"What we're discovering is that molecular, carbonaceous residues almost
always preserve a microscopic clue within fossils," said Jasmina Wiemann,
a graduate student in the Department of Earth & Planetary Sciences at
Yale and first author of the study. "Fossil organic matter is a wild
mix of things, based on the chemical degradation products of original biomolecules." Working with Yale paleontologist Derek Briggs and Yale
chemist Jason Crawford - - both co-authors of the study -- Wiemann
analyzed the molecular composition of 113 animal fossils dating back
541 million years. It is the largest fossil data set to be analyzed by
chemical means.

What they found was an abundance of soft tissues that fossilize into
polymers.

Recognizing these polymers and the soft tissues they represent may
help researchers determine how various animals relate to each other in evolutionary history.

"We show that proteins, lipids, and sugars in all types of animal
tissues converge in composition during fossilization through processes
such as lipoxidation and glycoxidation to form polymers," said Briggs,
the G. Evelyn Hutchinson Professor of Geology & Geophysics in the Yale
Faculty of Arts and Sciences.

Wiemann used Raman spectral analysis -- a non-destructive chemical
analysis technique -- to determine whether there are identifiable
biochemical signatures that survive within these polymers.

Thus far, she and her colleagues have found three main categories of signatures: biomineralization signals (which helped determine the soft
nature of early dinosaur egg shells); tissue signals that differentiate between, for example, insect cuticle and vertebrate cartilage (used to
identify the Tully Monster as a vertebrate); and phylogenetic signals
that are based on fossilization products of amino acids, revealing how
animals are related.

The researchers said understanding biological signatures in fossils has
the potential to fundamentally advance scientific knowledge about the
evolution of life on Earth.

"With this approach, we can go in a number of different research
directions, representing big questions for animal evolution with answers
that we thought were beyond the reach of fossils," Wiemann said.

Grants from the Yale Institute for Biospheric Studies and the Geological Society of America funded the research.


========================================================================== Story Source: Materials provided by Yale_University. Original written
by Jim Shelton. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jasmina Wiemann, Jason M. Crawford, Derek E. G. Briggs. Phylogenetic
and
physiological signals in metazoan fossil biomolecules. Science
Advances, 2020; 6 (28): eaba6883 DOI: 10.1126/sciadv.aba6883 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200713120028.htm

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