by From Will Dunham
Washington (Reuters) Showers in recent years have made progress in finding old DNA in fossils and gained an insight into organisms that lived a long time ago. But the oldest DNA, which has been preserved so far, comes from about two million years. Proteins, the molecular machinery of a cell, also offer valuable information and have virtue to survive much longer, as new research shows.
Scientists have now extracted and sequential proteins from dental fossils made of extinct rhinos, elephants and hippos, including a Rhino tooth tooth that is 21 to 24 million years old. Separate research teams found protein fragments in fossils from very different environments – the cold high Arctic Canada and a scorching rift Valley in Kenya.
“Together, these complementary projects show that proteins – basic building blocks of living organisms that preserve information about evolutionary history – can be found in old fossils worldwide,” said Daniel Green, leading author of the Kenya Fossils, the evolutionary biologist Daniel Green published in the journal Nature.
This opens up a new border to examine the deep evolutionary past, including human descent and maybe even the dinosaurs.
“Old proteins can tell us about the evolutionary history of an organism by providing molecular data from specimens for the preservation of DNA.
DNA and proteins are fragile and degraded over time, but proteins are more resistant. The oldest known DNA comes from organisms that lived in Greenland two million years ago. So far, the oldest known proteins had good enough to give insights into evolutionary relationships that were around four million years old from the Canadian Arctic.
The new research exceeds the borders of old protein research, a field called Paläofroteomik, by millions of years.
Proteins were preserved from the teeth of five rhino, elephant and hippopotamus species that lived in the Kenya Turkana region 1.5 to 18 million years ago. The proteins showed the connections between the old animals and their modern relatives.
Proteins were also extracted from a fragment of a tooth from an extinct rhino in a place called Haighton Crater in Nunavut, Canada’s northernmost territory, which was up to 24 million years old. They showed how this species fits into the Rhino trunk tree.
The cold and dry conditions of Haighton Crater were considered ideal for the preservation of proteins. The preservation of the hot climate of Turkana was unexpected.
DNA and proteins, basic molecules in biology, have different structures and functions. Desoxyribonucleic acid is the blueprint for life and has instructions for development, growth and reproduction of an organism. Proteins carry out numerous functions based on instructions from DNA.
“Proteins are encoded by our genetic code, DNA, so that protein sequences have information about the relationship between different individuals and organic sex,” said Green.
The scientists extracted peptides – chains of organic compounds, which are referred to as amino acids and form protein – found in tooth enamel.
“Some proteins help to build teeth, the toughest and most durable structures in animal bodies,” added Green.
“Most of the enamel is stone: a mineral called hydroxyapatite. But its formation is conveyed biologically by proteins that lead both shape and hardness over time. Since these proteins are deeply bordered in email, we have a reason that protein fragments can be preserved over many millions of years,” said Green.
Homo Sapiens appeared about 300,000 years ago. Old proteins were previously found in the teeth of some extinct species in the human evolutionary line, which are referred to as hominine. The Turkana region has produced important Hominin fossils.
“Hominine have evolutionary origins and/or diversification in the area in which our rehearsals are derived. Our results therefore promise in the future research of the melting product (proteins) of our evolutionary ancestors from the Turkana basin of the Kenya Education Conservation Institute in the Smithon Museum Institute in Maryland in Maryland.
The examined proteins came from large-body species from the age of the mammals, followed by the decline of the dinosaurs, which were dominated during the previous Mesozoic era, which ended 66 million years ago.
Green said that in the new research the number of proteins detectable decreased increasingly older fossils. But Green failed to find proteins from the age of the dinosaurs and to say: “Recent and better methods for extracting and capturing old proteins could perhaps push paleo -protoMik into the mesozoic.”
(Reporting according to Will Dunham, editing of Rosalba O’Brien)
