Chromosome 6 by Robin Cook.   Hardcover Jacket missing.  A harrowing new bestseller from the master of medical thrillers. A notorious underworld figure is gunned down and his body disappears from the city morgue before it can be autopsied. Soon, forensic pathologist Jack Stapleton finds himself being led down a grisly trail that takes him to the steamy jungles of equatorial Africa and a sinister surgical cabal.