Although the number of phylotypes seen in these samples
is impressive, it clearly underestimates the actual number
of bacterial species in these niches. Statistical analysis of
clone distribution estimated that the phylotypes actually
found in the fecal library comprise 85% of all the clones in
the library, while those seen in the plaque library represent
88% of the clones in the library. Further sequencing
might therefore have identified additional phylotypes.
Some species frequently observed in these niches were in
fact not found among the sequenced clones. Clones representing
Escherichia coli, the most famous of intestinal bacteria,
were not found, but E. coli and related facultative
anaerobes constitute only about 0.1% of the total bacterial