Human genome: how much do we know?

Lately, there has been a tremendous flurry of press and public activities worldwide surrounding the sequencing of the human genome.1xRival genome sequencers celebrate a milestone together. Marshall, E. Science. 2000; 288: 2294–2295Crossref | PubMed | Scopus (32)See all References1 It was recently announced that essentially the entire human DNA sequence has nearly been completed although some sections of it have not been resolved sufficiently accurately (http://www.ncbi.nlm.nih.gov/genome/seq/HsHome.shtml). Moreover, it has been published that ‘a multinational consortium reports the complete sequence of chromosome 21, the smallest human chromosome’ (2xRecounting a genetic story. Reeves, R.H. Nature. 2000; 405: 283–284Crossref | PubMed | Scopus (17)See all References2). Although the corresponding paper actually deals with sequencing only the long arm of this autosome, while its short arm (almost a quarter of chromosome 21!) remains virtually untouched, such a statement is quite justified given the title of that paper.3xThe DNA sequence of human chromosome 21. Hattori, M et al. Nature. 2000; 405: 311–319Crossref | PubMed | Scopus (780)See all References3As a result of this misinformation, there is a strong public belief that we already know virtually the whole sequence of the human genome. But, do things really look as good as they are presented to public? How complete is the known human DNA sequence de facto?The majority of sequence data is obtained as a so-called draft form that represents more than half of the genome. It should be thoroughly verified to correct numerous misreadings, which severely complicate the sequence analysis. Moreover, the draft version contains many gaps of unknown length with totally unidentified sequences. It is evidently difficult to clone and/or to read the DNA sequence within these gaps and it will therefore take a considerable amount of work for them to be sequenced. Consequently, the draft exists in unaligned segments of sequences, the true order of which is presently unknown.The public should also be aware that major efforts were invested into sequencing the euchromatic, gene-rich segments of chromosomes, whereas the condensed heterochromatin has been left essentially unread. However, although these chromosomal regions are rather small and poor in genes, they contain, along with important structural and regulatory elements, those genes that play key roles in early development.The Human Genome Project's ultimate goal is the construction of a map that portrays ‘all’ the human genes. A major milestone in reaching this goal is the ‘precise’, ‘ordered’ and ‘complete’ sequence of the entire human DNA. To correctly inform the public, scientists have to present the facts more clearly. Notwithstanding the great success of the sequencing enterprise, the truth is that the sequence data that is presently available are far from presenting the complete sequence map of our genome. As little as one-quarter of the human DNA has been completely sequenced to a high degree of accuracy.[4]xDraft data leave geneticists with a mountain still to climb. Butler, D and Smaglik, P. Nature. 2000; 405: 984–985Crossref | PubMed | Scopus (10)See all References, [5]xFinally, the book of life and instructions for navigating it. Pennisi, E. Science. 2000; 288: 2304–2307Crossref | PubMed | Scopus (57)See all References I think that a more careful presentation of scientific achievements will avoid otherwise inevitable public disappointment.