[vegedor]

It's an unjust counterexample, because religion is in our genetics, a tendency to symbolism, hierarchy and dogmatism, awe and fear of the unknown. Theism though is anything but durable in the face of scientific progress, but the same can be said about genes. It is durable only in ignorance.

Therefore faithful believe is a marker for predisposition, so the carrier will have to adapt or die out at which point the meme has to be revived, as the GP stated. Religions do change much quicker than the gene-pool. They hardly qualify as memetic if really anyone (counting in antheists with their own cults and rites modulo the theism) follows them, anyway.