GENETIC information from an extinct species of bison preserved in permafrost for thousands of years could help improve modern agricultural livestock and breeding programs, according to University of Adelaide researchers.
- Team analysed genetic mutations of ancient bison, modern ruminants.
- Tree goes back as far as 29 million years.
- Technique could be used to study other mammals.
Resea rchers from the university's Australian Centre for Ancient DNA (ACAD) worked with an international team of genomics researchers to analyse the genetic mutations of an ancient bison, many modern cattle breeds and members of the broader ruminant family tree, including deer, antelopes and giraffes.
The team paired a new approach to prepare ancient DNA with a new scientific technique developed specifically to genotype a cow to create the "very accurate and widespread" family tree, going back as far as 29 million years, according to an announcement from the University of Missouri.
This genetic information could allow scientists to understand the evolution of cattle, ruminants and other animals.
This same technique also could be used to help farmers develop healthier and more efficient cattle and assist scientists who are studying human diseases, the research group said in an article published in the October 20 Proceedings of the National Academy of Sciences.
"The entire ancient bison genome was screened using a bovine SNP (single nucleotide polymorphism) chip, which maps changes at 54,000 specific sites across the genome at once. This is the first time such a technique has been used to examine the genetic variation of any extinct species," said ACAD director Alan Cooper.
The bovine SNP chip was used to scan the genomes of 61 different ruminant species and 48 cattle breeds to create a detailed evolutionary history for this complex group, which has proven difficult to do using traditional genetic studies.
Study leader Jerry Taylor from the University of Missouri said: "We were surprised to find that we were able to generate very high-quality genotypes for species for which the chip was not designed."
By analysing a very large number of mutations across the different genomes, the researchers were able to provide a far more comprehensive picture of the ruminant family tree, as well as revealing the relationships and movements of modern cattle breeds through time.
The research revealed the history of European cattle, with domesticated cattle moving sequentially through Turkey, the Balkans and Italy, then spreading through Central Europe and France and ending in Britain.
The scientists also found evidence supporting a second route of ancient cattle into Europe by way of the Iberian Peninsula.
"Understanding how different genes create variation controlling growth efficiency, levels of marbling (intramuscular fat) and disease resistance could have a large economic impact for farmers who raise cattle throughout the world," Taylor said.
ACAD post-doctoral researcher Dr Kefei Chen has since used the approach to analyse the genomes of extinct aurochs, the ancestor of modern cattle, as well as early domestic cattle from China, Russia and Europe.
"We are using this approach to track genetic changes that took place during domestication, when much of the diversity in ancestral species was lost due to the very strong selection applied by early farmers for a few genetic traits such as docility, rapid growth and birth rates," Cooper said.
Using the marbling example, the researchers said if breeds of cattle with high amounts of marbling are closely related to each other, then they likely share the same gene variations to create the marbling, which is a trait some beef consumers prefer.
On the other hand, if those same cattle are not closely related, different genetic variants might be at work.
"This also provides us an opportunity to identify animal models for human disease since, for example, an excess amount of intramuscular fat in humans is associated with insulin resistance and type 2 diabetes," Taylor said.
"We're all interested in reconstructing our ancestry. This is essentially the same thing, except that we're able to zoom out by millions of years and include relatives who are long gone.
"The amazing thing about this technique is that it is very fast and extremely cheap. For relatively small amounts of money, we can generate the data that will allow us to recreate millions of years of evolutionary history," he said.
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