The sequencing made it possible to compare M. jannaschii's total complement of genes with the many genes that have so far been sequenced in other organisms. Forty-four percent of M. jannaschii's genes resemble those in bacteria or eukarya, or both. And consistent with Woese's scheme, fully 56 percent are completely different from any genes yet described. That M. jannaschii has characteristics of bacteria and eukarya but also has marked differences suggests that archaea and the other two lineages have a common distant ancestor. Later, the eukarya split off from the archaea.
Scientists are eager to learn the nature of the genes that are unique to archaea.
Genes are the blueprints from which enzymes and other proteins important to cell structure and function are made. Many of the unique archaeal genes undoubtedly encode novel proteins that may provide insights into how ancient cells survived. And certain of these unusual proteins can probably be enlisted for developing innovative medicines or to perform new tricks in industry. Methanococcus jannaschii, a spherical cell with many flagella, was among its finds in 1982. The diagram on the opposite page depicts the three major evolutionary lineages of life.