Factual error: The atmosphere pressure of Mars is 0.07 Bar, Earth is 1 Bar, about 14 times greater. Yet the plastic covering of the greenhouse is shown flapping with the outside breeze. With the inside of the greenhouse having an Earth-like environment its plastic covering would have been inflated like a balloon against the weaker Mars atmosphere.
Factual error: Their complete and utter disregard for the most basic scientific facts in this movie is amazing. It's already been said that Gary Sinise couldn't possibly have recognised the DNA sequence as human (that segment may have been enough to produce a single protein common to any lifeform). The thing that gets me is that he recognises that the DNA is missing a couple of "chromosomes" to complete it. DNA is made of units called nucleotides (remember A,T,C,& G?); chromosomes are formed by huge strings of DNA wound together (not the other way around). You don't need a degree in Biology to know this, you just need to have stayed awake in high school.