Fine Read­ing: Mi­cro­bial Evo­lu­tion

by Merry Youle

Dar­win fo­cused his at­ten­tion on vis­i­ble life forms…and there the evo­lu­tion­ary fo­cus re­mained un­til re­cent decades when the mi­crobes seized the lime­light. The Amer­i­can Acad­emy of Mi­cro­bi­ol­ogy (ASM's hon­orific lead­er­ship group) ac­knowl­edged this over­due shift two years ago, on the 150^th an­niver­sary of pub­li­ca­tion of On the Ori­gin of Species. The AAM brought to­gether 34 mi­cro­bi­ol­o­gists with di­verse spe­cial­ties to par­tic­i­pate in a col­lo­quium held in the Gala­pa­gos Is­lands (where else?). What, they col­lec­tively won­dered, would Dar­win have made of the mi­cro­bial world?

Some an­swers are shared in the col­lo­quium re­port re­cently pub­lished by the AAM. For read­ers of this blog, al­ready among the con­verted, the re­port pro­vides a co­gent sum­mary of the im­por­tance of mi­cro­bial evo­lu­tion for all life on Earth—past, present, and fu­ture. The report's clear and at­trac­tive pre­sen­ta­tion makes it also well-suited for use when pros­e­ly­tiz­ing to those who tend to ig­nore The Small Things. As you would ex­pect, it re­minds us that for bil­lions of years, mi­cro­bial evo­lu­tion was the only evo­lu­tion, and that to­day most of the ex­tant bi­o­log­i­cal di­ver­sity is mi­cro­bial. Fur­ther, it points out that many of the mech­a­nisms dri­ving the evo­lu­tion of both mac­robes and mi­crobes were dis­cov­ered by study­ing the lat­ter. Study­ing mi­cro­bial evo­lu­tion is also use­ful in a prac­ti­cal sense as we seek new ways to tai­lor mi­crobes for our own pur­poses (e.g., con­trol­ling dis­ease, biosyn­the­sis of use­ful ma­te­ri­als, biore­me­di­a­tion). De­spite method­olog­i­cal ad­vances, these stud­ies re­main chal­leng­ing due to the vast di­ver­sity of the mi­crobes, their ram­pant gene swap­ping, and their abil­ity to adapt at both the in­di­vid­ual and com­mu­nity level.

This re­search takes on an added im­por­tance to­day be­cause of the key role of the mi­crobes in mod­i­fy­ing and main­tain­ing the global sys­tems that sup­port life on Earth. As we go pur­blindly about per­turb­ing en­vi­ron­men­tal sys­tems in count­less ways, some are ask­ing: How re­silient are these sys­tems? How will the mi­crobes re­spond? In the tra­di­tion of these col­lo­quia, the re­port con­cludes with well-founded rec­om­men­da­tions for how to pur­sue the an­swers. Key cur­rent re­search ques­tions are high­lighted, as well as po­ten­tially fruit­ful re­search di­rec­tions. In brief, the re­port re­minds us that if you want an­swers to such ques­tions, ask the mi­crobes.