The noncoding part of the genome

The noncoding part of the genome that’s mostly
junk DNA (the heterochromatin) has been tough
to work with because it’s made up of repetitive
sequences. All that repetition makes putting the
sequences into their proper order extremely difficult.
Some scientists think it may be another five
years before the Human Genome Project is truly
complete in the sense that the entire sequence
of the whole human genome is known. Even a
complete HGP leaves much left to learn;