Before revision:  Based on our results we describe a set of 2,001 genes that have no protein features and poor conservation, or have ambiguous annotations in gene or protein databases. We suggest that many of the genes that lack supporting evidence and that are not detected in proteomics experiments, do not code for proteins under normal circumstances and that they should not be included in the human protein coding gene catalogue.
After revision:  Based on our results we describe a set of 2,001 genes that are potentially non-coding, and show that many of these genes behave more like non-coding genes than protein-coding genes. We detect peptides for just 3\% of these genes. We suggest that many of the genes that lack supporting evidence and that are not detected in proteomics experiments, do not code for proteins under normal circumstances and that they should not be included in the human protein coding gene catalogue.