The effect of age on the abundance of several bacteria groups is sex specific.

<p>Heat-maps showing the abundance of several bacteria that differed significantly between young (3 months) and old (19 months) males and females. A box indicates bacteria which have a significantly different abundance between the two groups within that box. Colors indicate relative abundances normalized per bacterial group (per row), dark blue is the lowest abundance and dark red the highest abundance detected over all the samples of a bacterial group.