Why Aren't All Members of a Species the Same? Exploring the Pangenome

Prochlorococcus marinus are diminutive organisms. At less than a micrometer across, these photosynthesizing microbes may be small, but they’re plentiful – by many accounts one of the most abundant species on the planet. But that’s not quite the full story: like any other member of the same species, no two P. marinus individuals are genetically identical. What’s remarkable is how different they may be. Take two different P. marinus cells from different parts of the ocean, sequence their ge