11.   Comuzzie said the POMC gene has a complicated role in the regulation of several important body systems, particularly in the brain.

12.   How many genes have to work together?

13.   If a variant gene has a counterpart copied onto another chromosome, the counterpart gene is likely to be involved in similar disease conditions, Celera authors have found.

14.   In larger populations, a particular gene may have different DNA changes, or mutations, in different patients, making each mutation harder to spot.

15.   Most human genes have an ancestry that goes back to the earliest animals and is shared in common with other species.

16.   Mouse genes have human counterparts.

17.   Regardless of its acronym, the sex-reversal gene has several confounding properties that will take considerable insight to decode.

18.   The individual genes have to be classified according to what they do and how they function in the body.

19.   The other thousand genes have no match and have unknown roles.

20.   The pyruvate gene has no obvious correlation with any known difference among major population groups.