The origin of this gesture is highly speculative, but is quite possibly thousands of years old. It is identified as the digitus impudicus (“impudent finger”) in Ancient Roman writings[1] and reference is made to using the finger in the Ancient Greek comedy The Clouds by Aristophanes. It was defined there as a gesture intended to insult another. The widespread usage of the finger in many cultures is likely due to the geographical influence of the Roman Empire and Greco-Roman civilization. Another possible origin of this gesture can be found in the first-century Mediterranean world, where extending the digitus impudicus was one of many methods used to divert the ever present threat of the evil eye.[2]

Thumbs up:

The source of the gesture is obscure, although Carleton S. Coon, having observed Barbary apes in Gibraltar using the gesture, hypothesised in the anthropological classic ‘The Story of Man’ that it is a mutual celebration of having opposable thumbs. Critics have suggested, however, that the apes may have simply be aping man.

http://www.funtrivia.com/askft/Question50571.html and the origin of the ‘Thumbs up’