mtDNA NADH dehydrogenase subunit 2 sequence data is unable to properly resolve the relationships of the species. Judging from New World jay biogeography, the unicolored or Mexican jays might represent the most basal lineage; morphology would tentatively lean towards the latter which retains more of the group's color patterns, while the available molecular data allows no robust conclusions whatsoever. In any case, the data of Rice "et al." (2003) suggests – albeit also with very low confidence – that the Mexican jay comprises two clades which might constitute two separate species. However, far too few individuals have been sampled to say anything definite on that matter, except that the lineages – if they indeed exist – do not correspond to the geographical pattern of intraspecific variation (see species article for more).