Before revision:  We find that there are surprisingly strong correlations between peptide detection and cross-species conservation, gene age and the presence of protein-like features. The age of the gene  and its conservation across vertebrate species are key indicators of whether a peptide will be detected in proteomics experiments.
After revision:  We find the age of the gene and its conservation across vertebrate species are key indicators of whether a peptide will be detected in proteomics experiments.