[neeeeees]

It’s an intentionally misleading tweet.

To simplify, It’s saying, if the genome were a string of some length, for any possible byte b and byte position i, there exists a person whose genome has b at position i. Unlike normal character strings, there are only 20 or so valid characters (proteins) encoded by 3 “bytes” (nucleotides) each. So you’re looking at O(10 billion) values of (i, b) that would still keep the string well-formed in its 3-bytes-per-character encoding.

Most importantly, it’s not saying anything about having some bytes b1 and b2 at the ith and jth positions or any generalization thereof.