A Caudipteryx zoui fossil cast. (Daderot/Wikimedia Commons/CC0 1.0) The remnants of DNA may lurk in 125 million-year-old dinosaur fossils found in China. If the microscopic structures are indeed DNA, they would be the oldest recorded preservation of chromosome material in a vertebrate fossil. DNA is coiled inside chromosomes within a cell's nucleus. Researchers have reported possible cell nucleus structures in fossils of plants and algae dating back millions of years. Scientists have even suggested that a set of microfossils from 540 million years ago might hold preserved nuclei. These claims are often controversial, because it can be hard to distinguish...