title: Metagenomics of mouse intestinal microbiome : 24 months colon F1 CR
design: DNA extraction: Fecal DNA was extracted from luminal fecal samples of cecum and colon using PowerFecal kits (Qiagen) according to the manufacturers instructions, with the exception that, rather than performing the initial homogenization of samples using the vortex adapter described in the protocol, samples are homogenized in the provided bead tubes using a TissueLyser II (Qiagen, Venlo, Netherlands) for three minutes at 30/sec, before proceeding according to the protocol and eluting in 100 L of elution buffer (Qiagen).  DNA yields are quantified via fluorometry (Qubit 2.0, Invitrogen, Carlsbad, CA) using quant-iT BR dsDNA reagent kits (Invitrogen).