Example of and lack of paralog exchange. Left panel: example of Lamb1-1 already being expressed higher relative to other paralogs and its gene expression not changing much from pre- to terminal-differentiation. Lamb1-1:dark blue;Lambc2:pink;Lamb3:light blue. Right panel: example of switching to a tissue specific paralog from myoblast to myotube. Flnc (a component of the Z-disk) which is muscle specific is up-regulated and non-muscle specific paralogs are down-regulated. Flna: orange; Flnb: green; Flnc: red.