[onemoreact]

We have the raw data on the actual DNA for several people which is what you need to make a copy. What we don't know is what the data means and what all the mutations are in the wild. Which is what you want to know if we are going to start making changes.

[iang]

Actually we don't have the full DNA sequence for any human. For example, if you look at the data from say the Genome Reference Consortium the first 10,000 bases on Chromosome are designated as N - unknown.

[bthomas]

True that we don't have a full sequence, but that's not the best example. The telomeres (ends) consist of the same set of bases repeated thousands of times. Recent research suggests that the length is probably super important. We're good at approximating length, but not detecting exactly.

There are a bunch of regions of 'N' in the reference sequence, most are just repeats.

The genome is incredibly complex, and yes, much we still can't represent accurately. As one example, some genes are given a location in the reference genome, while every person actually has multiple copies that are scattered across the genome.