In 1995, a report on the entire DNA sequence for the genome of the bacteria Haemophilus influenzae was published . Although the genomes for a number of viruses had been completed before this, H. influenzae was the first free-living organism to have it's genome sequenced, and as such, this report remains a biological milestone. Since then, the entire genome sequences for over 10 microorganisms have been compiled and released and more are on their way. The completed microbial genomes include:

Haemophilus influenzae finished 1995

Mycoplasma genitalium finished 1995

Methanococcus jannaschii finished 1996

Mycoplasma pneumoniae finished 1996

Saccharomyces cerevisiae finished 1997

Archaeoglobus fulgidus finished 1997

The benefits of complete genome sequencing projects include a greater understanding of the organisms being sequenced and acknowledgment of the minimum complement of genes necessary for a free-living organism. Of the organi

Because the universal phylogenetic tree brings us face to face with the great evolutionary questions, our growing ability to formulate these in molecular and genetic terms is particularly exciting. We can now inquire about the origins of not only the eucaryotic cell, but also parts of the eucaryotic genome. In particular we can now ask for what fraction of eucaryotic genes is the most similar homolog an archaeal gene or a bacterial gene and for what fraction is there no detectable homolog? We can also inquire about the genetic processes that were involved in the evolution of extant life. The origins of key cellular functions can now also be addressed. In particular, the extent to which we can trace genes back to a basic genetic complement is expanding as more and more organisms have their complete genomes sequenced. The answers to all of these questions are vital in shaping the microbial phylogeny that is developing.

The sequencing of the M. jannaschii genome has also given some insights into the archaea's evolutionary relationships to the bacteria and the eucarya. It is important to note that the root of the tree separates the Bacteria from the other two groups. This separation makes the Archaea and the eucaryotes specific (although distant) relatives, evidenced by the observation of many similarities between the two groups. For example, in all information processing systems, that is, translation, transcription and DNA replication, the archaeal and eucaryotic versions resemble each other a great deal more than either genome resembles the bacterial version . Other resemblances between Archaea and eucaryotes include histones, cell division proteins, proteosomes, and protein transport systems. Despite these similarities, the archaea resemble the bacteria in morphology and metabolism. It has been speculated, as a result of comparisons of genome sequences from all domains of life, that extent archaea may be descendants of the long-postulated procaryotic ancestor of the eucaryotes. The primitive nature of the archaea further supports this suggestion. M. jannaschii, for example, is a complete autotroph. That is, the organism requires no organic nutrients for growth. Recent announcements of possible fossils in a Martian meteorite have fuelled suggestions that the original archaea arrived on such a meteorite, and was able to survive in the absence of any organic matter.

Prior to the 1960's, evolutionary study had been confined to

Some common words found in the essay are:
Bacteria Eucarya, Sequencing Microbiology, Organisms Pseudomonas, Age Exploration, genome sequencing, phylogenetic classification, finished 1997, molecular studies, microbial phylogeny, genome sequencing projects, finished 1996, genome sequences, free-living organism, view life, sequencing projects, free-living organism it's, complete genome sequencing, universal phylogenetic tree,
Approximate Word count = 1647
Approximate Pages = 7 (250 words per page double spaced)