Weird >From lines in mail and news

[utzoo!decvax!yale-com!hawley]

Occasionally, a "From" line in a news or mail item
is mysteriously transformed into a ">From" line by "mail", 
and possibly by other programs (like uucp, news) as well.

I can't seem to find any explanations for this anywhere,
(it seems to be just a Unix quirk, and I don't believe it's
part of the ARPA standard mail header)
but I have reason to believe that this quirk has caused
the loss of "From" lines in locally forwarded mail here at Yale.
This is not too nice.  You can get long distance mailings,
but have no idea where the hell the damn things came from!

Why does this happen?  What does it all mean?

battling the software crisis with burning intensity,
Mike Hawley