In:
eLife, eLife Sciences Publications, Ltd, Vol. 5 ( 2016-09-27)
Abstract:
The pattern of chemical reactions that break down the molecules that make our bodies is still fairly mysterious. Archaeologists and geologists hope that dead organisms (or artefacts made from them) might not decay entirely, leaving behind clues to their lives. We know that some molecules are more resistant than others; for example, fats are tough and survive for a long time while DNA is degraded very rapidly. Proteins, which are made of chains of smaller molecules called amino acids, are usually sturdier than DNA. Since the amino acid sequence of a protein reflects the DNA sequence that encodes it, proteins in fossils can help researchers to reconstruct how extinct organisms are related in cases where DNA cannot be retrieved. Time, temperature, burial environment and the chemistry of the fossil all influence how quickly a protein decays. However, it is not clear what mechanisms slow down decay so that full protein sequences can be preserved and identified after millions of years. As a result, it is difficult to know where to look for these ancient sequences. In the womb of ostriches, several proteins are responsible for assembling the minerals that make up the ostrich eggshell. These proteins become trapped tightly within the mineral crystals themselves. In this situation, proteins can potentially be preserved over geological time. Demarchi et al. have now studied 3.8 million-year-old eggshells found close to the equator and, despite the extent to which the samples have degraded, discovered fully preserved protein sequences. Using a computer simulation method called molecular dynamics, Demarchi et al. calculated that the protein sequences that are able to survive the longest are stabilized by strong binding to the surface of the mineral crystals. The authenticity of these sequences was tested thoroughly using a combination of several approaches that Demarchi et al. recommend using as a standard for ancient protein studies. Overall, it appears that biominerals are an excellent source of ancient protein sequences because mineral binding ensures survival. A systematic survey of fossil biominerals from different environments is now needed to assess whether these biomolecules have the potential to act as barcodes for interpreting the evolution of organisms.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.17092.001
DOI:
10.7554/eLife.17092.002
DOI:
10.7554/eLife.17092.003
DOI:
10.7554/eLife.17092.004
DOI:
10.7554/eLife.17092.005
DOI:
10.7554/eLife.17092.006
DOI:
10.7554/eLife.17092.007
DOI:
10.7554/eLife.17092.008
DOI:
10.7554/eLife.17092.009
DOI:
10.7554/eLife.17092.010
DOI:
10.7554/eLife.17092.011
DOI:
10.7554/eLife.17092.012
DOI:
10.7554/eLife.17092.013
DOI:
10.7554/eLife.17092.014
DOI:
10.7554/eLife.17092.015
DOI:
10.7554/eLife.17092.016
DOI:
10.7554/eLife.17092.017
DOI:
10.7554/eLife.17092.018
DOI:
10.7554/eLife.17092.019
DOI:
10.7554/eLife.17092.020
DOI:
10.7554/eLife.17092.021
DOI:
10.7554/eLife.17092.022
DOI:
10.7554/eLife.17092.023
DOI:
10.7554/eLife.17092.024
DOI:
10.7554/eLife.17092.025
DOI:
10.7554/eLife.17092.026
DOI:
10.7554/eLife.17092.027
DOI:
10.7554/eLife.17092.028
DOI:
10.7554/eLife.17092.029
DOI:
10.7554/eLife.17092.030
DOI:
10.7554/eLife.17092.031
DOI:
10.7554/eLife.17092.032
DOI:
10.7554/eLife.17092.033
DOI:
10.7554/eLife.17092.034
DOI:
10.7554/eLife.17092.035
DOI:
10.7554/eLife.17092.042
DOI:
10.7554/eLife.17092.043
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2016
detail.hit.zdb_id:
2687154-3
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