Genome of 700,000-year-old horse sequenced

The oldest genome so far from a prehistoric creature has been sequenced by an international team, led by scientists from the Natural History Museum of Denmark (University of Copenhagen). The team, which included Dr Jakob Vinther of the University of Bristol, sequenced and analysed short pieces of DNA molecules preserved in bone-remnants from a horse frozen for the last 700,000 years in the permafrost of Yukon, Canada. By tracking the genomic changes that transformed prehistoric wild horses into domestic breeds, the researchers have revealed the genetic make-up of modern horses with unprecedented detail. DNA molecules can survive in fossils well after an organism dies, not as whole chromosomes but as short pieces that could be assembled back together, like a puzzle. Sometimes enough molecules survive so that the full genome sequence of an extinct species could be resurrected and over the past few years, the full genome sequence of a few ancient humans and archaic hominins has been characterized - but so far, none dated back more than 70,000 years. Now Dr Ludovic Orlando and Professor Eske Willerslev from Copenhagen's Centre for GeoGenetics and colleagues have beaten this DNA-record by about 10 times. Sequencing the first genome from the Middle Pleistocene was by no means straightforward and involved collaboration between researchers from Denmark, China, Canada, the USA, Switzerland, the UK, Norway, France, Sweden and Saudi Arabia.