Like a duplicated gene, the two seem to have evolved in different directions over time.
I've read that Torah scrolls have the same kind of transcription errors "inherited" from one copy to the next so the origin of a scroll can be traced back.
I've read that Torah scrolls have the same kind of transcription errors "inherited" from one copy to the next so the origin of a scroll can be traced back.
http://en.wikipedia.org/wiki/Documentary_Hypothesis
Also, I'm not quite sure what kind of transcription errors are permitted in Torah scrolls. They do throw out the entire scroll if there's a significant error. I can't imagine someone duplicating an entire psalm. At most, a letter might be missing from the text.
Hand-copying text is error-prone, and copies are often made from copies, so there's the chance to reconstruct a "family tree" even after knowledge of what copied from what is lost.
See, for example, this: http://ahds.ac.uk/archaeology/creating/case-studies/canterbu...