Does Google PR is actually based on number of Backlinks?

[www.GameFriends.com]

This is probably under the same phenomenon of Squidoo pages of the past ranking extremely highly with PR and now Twitter. Sometimes the age of a domain can give a website higher PR than normal. On average though, the specific pages PR is based off how many websites and the quality of them link to it, and this includes interlinking of your own webpages.

[Robdale]

Agree with the domain age point. But whatever i have heard, is it true? That google now don't give any importance to backlinks. If this is true then what are the other ways to gain high PR?