It Was Discovered From Modern Humans
Experts extracted proteins from the tooth of a Homo antecessor in this case. The amino acid sequences in these strands were then reconstructed. The amino acids discovered in proteins from modern humans, Neanderthals, and Homo heidelbergensis, a species that lived 700,000 to 300,000 years ago, were then analyzed in the same way.

It Was Discovered From Modern Humans
Modern Humans Have Full DNA
The researchers didn’t have to extract the proteins from enamel in modern humans because they already had full DNA sequencing to work with. It would have been ideal to be able to accomplish the same thing with Homo antecessor’s genetic code, but that information did not survive the test of time as well as the enamel-bound protein.

Modern Humans Have Full DNA