It’s a mystery that has long plagued researchers, but the question of where and when modern horses were first domesticated may have been finally put to bed – in a stable, of course. A new study published in Nature yesterday has found that the DNA of all modern horses can be traced back to a group that lived in the Western Steppes of Russia 4,200 years ago. Within a few centuries, domesticated horses spread across Asia and Europe, and then they were everywhere. Researchers say gee-gees helped shape human civilisation because they could take our ancestors’ to faraway places, pull heavy things and help out in agriculture. It’s nothing to neigh at…