Chlamydia genomics: providing novel insights into chlamydial biology

• Chlamydia lacks several biosynthetic pathways and must rely on the host to survive.
• Minor genetic changes can lead to colonization of different tissues.
• Genomics can assist with the design of genetic transformation experiments.
• There has been a recent increase in the amount of Chlamydia genomes published.

Chlamydiaceae are obligate intracellular pathogens that have successfully evolved to colonize a diverse range of hosts. There are currently 11 described species of Chlamydia, most of which have a significant impact on the health of humans or animals. Expanding chlamydial genome sequence information has revolutionized our understanding of chlamydial biology, including aspects of their unique lifecycle, host–pathogen interactions, and genetic differences between Chlamydia strains associated with different host and tissue tropisms. This review summarizes the major highlights of chlamydial genomics and reflects on the considerable impact these have had on understanding the biology of chlamydial pathogens and the changing nature of genomics tools in the ‘post-genomics’ era.