Chevy Colorado I5 engine

I was on this site called Coloradofans.com, and they were talking about the colorado I5 engine. They said that GM made it off of the I4 and I6. I thought the engine came from SAAB and GM just built it better. Are they right or do they have no idea what they are talking about? Thanks

Last I heard the I-5 is an i-6 missing a cylinder.