posted on Jan, 10 2010 @ 11:15 PM
Or we could take the more logical (and likely) stance that, since viruses must by nature insert their DNA into our cells' genomes to replicate, some
bits and pieces were improperly left in the host's genome. Allow this to happen for millenia and you will begin to see a sizeable number of genes
with some viral components.
Natural processes are far from perfect. It's reasonable to assume that problems have arisen involving viruses and DNA excision during replication.