One example for both sides:
1) That article comes from Fox News or MSNBC or the New York Times or the Wall Street Journal, so it can't be trusted.
It is certainly true that news outlets have their biases, as does everyone, and such bias can lead to distortion, but rejecting information only because of where it comes from is a logical fallacy. One's bias does not necessarily interfere with the truth, otherwise no one can know or speak the truth. To reject an argument because of the source is an attempt to dismiss an argument, not on its merits or the lack thereof, but simply because the source is bias in the other direction of the one dismissing it.
Employing the genetic fallacy is a lazy way to argue and requires little thought.
The next logical fallacy: false cause.