Ancient DNA retrieved from extinct horse species from around the world has challenged one of the textbook examples of evolution - the fossil record of the horse family Equidae over the past 55 million years. The study, published today in the Proceedings of the National Academy of Sciences, involved an international team of researchers and the Australian Centre for Ancient DNA (ACAD) based at the University of Adelaide. Only the modern horse, zebras, wild asses and donkey survive today, but many other lineages have become extinct over the last 50,000 years. ACAD Director Professor Alan Cooper says despite an excellent...