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Comparisons with their closest free living cyanobacteria of the genus " Synechococcus " ( having a genome size 3 Mb , with 3300 genes ) revealed that chromatophores underwent a drastic genome shrinkage .
 Synechococcus
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Synechococcus