Nathan Koren wrote:
They jump between us and other mammals with less frequency, between us and reptiles less frequently than that, and between us and plants -- never.

Alex writes:
Never is fairly bold assertion, and being a negative, cannot be conclusively proven. At any rate, there are a few exceptions to diseases crossing over to humans, but it is true that other factors may have been involved (e.g. the human had other complicating factors such as severe burns, etc.).

Nathan Koren wrote:
Anything living on Mars will be a LOT less related to us than terrestrial plants!

Alex writes:
Really? Of course, you have positive evidence (rather than heuristic plausibility arguments) to back up that statement? On the rather safe assumption that you have no such evidence, prudence dictates a more cautious approach.

Look, I think that DiGregorio's thesis is nothing more than alarmist hand-waving; however, I think that Zubrin (in his single-minded zealotry) has glossed over the whole issue by oversimplification.

Alex R. Blackwell
University of Hawaii