“…The frequencies of such exchanges in the wild are not known (e.g.,
George et al , 1983; Haggard-Ljungquist et al , 1992; Sandmeier et al , 1992; Stummeyer et al , 2006; Pickard et al , 2010; Casjens and Thuman-Commike, 2011; Jacobs-Sera et al , 2012), but some measurements have been performed in the laboratory ( e.g. , De Paepe et al , 2014). Such horizontal exchange complicates whole phage genome comparisons and will make any hierarchical classification scheme nonsensical if it is great enough (Lawrence et al , 2002).…”