"Robert J. Kolker" <bobkolker@comcast.net> wrote in
news:fGuVa.9671$o%2.5773@sccrnsc02: 

Even if there were a natural source of primes, it would take an 
intelligence to build a device for transmiting the output of that
source. 

However: the distribution pattern of leafs around a branch or the petals of 
a flower seems to suggest a pattern based on prime numbers.
So it looks like there are natural sources of primes...