> the proteins we see today may in some sense be formed out of primordial peptides. This seems reasonable, but another possibility is that modern proteins (dom

> the proteins we see today may in some sense be formed out of primordial peptides. This seems reasonable, but another possibility is that modern proteins (domains) are 'carved' from larger proteins that had a looser structure. In other words, primordial proteins could have been badly folded and mutations gradually improved them to smaller, better folded structures.