Ancestor-derived genes that were lost in the small <i>Prochlorococcus</i> but are retained in the extant <i>Synechococcus</i> genomes.

<p>A subset of 1641 ancestor-derived genes was identified from the 2028 genes in the reconstructed last common ancestor genome due to their presence in the 5 marine <i>Synechococcus</i> genomes. This subset is further divided into two groups: (1) the Lost group, which contains genes that are lost in the <i>Prochlorococcus</i> genomes; and (2) the Retained group, which contains genes that are kept in the <i>Prochlorococcus</i> genomes.