Table 1. Classification of the 173 gaps in amino acid biosynthesis pathways in 10 bacteria.

Group	Subgroup	Cases
Clear candidate	multiple candidates	9
	auxotrophic	61
	essential	54
	no fitness data	9
	other (redundant)	5
	other	2
Gene model error		2
Transaminase		18
Known gap		2
Genuine gap	filled (this study)	9
	unfilled	2