What percentage of the human genome hasn't been sequenced yet? I have read different estimates, e.g.:
- https://www.genome.gov/human-genome-project/Completion-FAQ (mirror): "In the April 2003 version, there are less than 400 gaps and 99 percent of the genome is finished with an accuracy rate of less than one error every 10,000 base pairs"
- https://www.statnews.com/2017/06/20/human-genome-not-fully-sequenced/ (mirror): "Church estimates 4 percent to 9 percent of the human genome hasn’t been sequenced. Miga thinks it’s 8 percent."
If there isn't a consensus on the percentage of the human genome that hasn't been sequenced yet, why is it difficult to estimate?