Publishing Priority Punchdown at PLoS ONE

A fascinating discussion point has arisen in the context of discussing a recent paper in PLoS ONE.
Wang X, Sun Q, McGrath SD, Mardis ER, Soloway PD, et al. (2008) Transcriptome-Wide Identification of Novel Imprinted Genes in Neonatal Mouse Brain. PLoS ONE 3(12): e3839. doi:10.1371/journal.pone.0003839
The comment thread is, as of this writing, populated primarily by one contributor with responses by the senior author. My eye was drawn to a comment exchange that focused on issues of crediting other work and publication priority.