by By Will Dunham
In recent years, Washington (Reuters) scientists have made progress in finding old DNA in fossils, giving insight into organisms that lived long ago. But the oldest DNA obtained so far dates around two million years. Proteins, the molecular machines of a cell, also offer valuable information and have the virtue to survive much longer, as new research shows.
Scientists have now extracted proteins and sees themed from dental fossils of extinct rhinos, elephants and hippopotamussen, including a nasal horn 21-24 million years old. Separate research teams found protein fragments in fossils from very different environments – the ice -cold High Arctic from Canada and a burning gap valley in Kenya.
“Together, these complementary projects show that proteins – fundamental building blocks of living organisms that retain information about evolutionary history – can be found in old fossils around the world,” said evolutionary biologist Daniel Green, main author of the Harvard University, main author of the Kenya Fossil -Study.
This opens a new limit for investigating the deep evolutionary past, including human descent and perhaps even dinosaurs.
“Old proteins can tell us about the evolutionary history of an organism by giving molecular data from copies that are too old for DNA conservation. This allows researchers to clarify evolutionary relationships in the tree of life, even for species that extinction millions of years ago,” said Ryan Sinclair of the Postdoctor of the University of the University of the University of the University of the University of the University, the Postdoctor. University of nature.
DNA and proteins are vulnerable and relegate over time, but proteins are more resilient. The oldest known DNA is from organisms who lived in Greenland two million years ago. Until now, the oldest known proteins that were well enough were kept to provide insight into evolutionary relationships of about four million years old, from the Canadian North Pole area.
The new research pushes back the boundaries of the old protein research, a field called Paleoproteomics, with millions of years.
Proteins were obtained from teeth of five rhino, elephant and hippo species that lived in the Turana region 1.5-18 million years ago in Turana. The proteins showed the ties between the old animals and their modern family members.
Proteins were also extracted from a fragment of a tooth of an extinct rhino on a site called Haughton Crater in Nunavut, the northernmost territory of Canada, which was up to 24 million years old. They showed how this species fit in the nose hos trolley tree.
The cold and dry conditions of Haughton Crater were considered ideal for retaining proteins. Retaining in the hot climate of Turkana was more unexpected.
DNA and proteins, fundamental molecules in biology, have different structures and functions. Deoxyribonucleic acid is the blueprint for life, with instructions for the development, growth and reproduction of an organism. Proteins perform countless functions based on DNA instructions.
“Proteins are coded by our genetic code, DNA, so protein sequences reveal information about kinship between different individuals and biological sex, among other things,” said Green.
The scientists extracted peptides – chains of organic compounds called amino acids that combine to form proteins – found in tooth enamel.
“Some proteins help to build teeth, the most difficult and sustainable structures in animal bodies,” Green added.
“Email is usually rock: a mineral named hydroxyapatite. But their formation is biologically mediated by proteins that lead both form and hardness over time. Because these proteins are deeply buried in the email, we have a reason to expect that protein fragments can be stored 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 human evolutionary origin, called Hominins. The Turkana region has delivered important human -like fossils.
“Hominins have evolutionary origin and/or diversification in the area where our samples come, so our results have a promise in the future exploring the email proteom (set of proteins) of our evolutionary ancestors of the Turkana basket of Kenya,” said research scenon Timothy Instelande, a physical author’sist, a physical author’s artist ethe, a physical author’s artist TELANTUTEIUTE. Maryland.
The proteins investigated came from large species from the age of mammals that followed the downfall of the dinosaurs that had dominated during the previous Mesozoic era, which ended 66 million years ago.
Green said that in the new study the number of detectable proteins in ever -older fossils decreased. But Green does not rule out proteins that date from the age of dinosaurs and said: “Newer and better methods for extracting and detecting old proteins might be able to push paleoproteomics into the Mesozoic.”
(Reporting by Will Dunham, editing by Rosalba O’Brien)
