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The Sorcerer II Global Ocean Sampling Expedition: Northwest Atlantic through Eastern Tropical Pacific

Figure 3

Population Structure and Variation as Revealed by Phylogeny

Phylogenies were produced using neighbor-joining. There is significant within-clade variation as well as an absence of strong geographic structure to variants of SAR11 (P. ubique HTCC1062) and P. marinus MIT9312. Similar reads are not necessarily from similar locations, and reads from similar locations are not necessarily similar.

(A) Geographic distribution of SAR11 proteorhodopsin variants. Keys to coloration: blue, Pacific; pink, Atlantic.

(B) Geographic distribution of Prochlorococcus variants. Keys to coloration: blue, Pacific; pink, Atlantic.

(C) Origins of spectral tuning of SAR11 proteorhodopsins. Reads are colored according to whether they contain the L (green) or Q (blue) variant at the spectral tuning residue described in the text. The selection of tuning residue is lineage restricted, but each variant must have arisen on two separate occasions.

Figure 3