examined ZII immunoreactivity in a paleognath, the Chilean tinamou (Nothoprocta perdicaria). In the tinamou, Purkinje cells expressed ZII heterogeneously such that there were sagittal ZII+ and ZII-stripes of Purkinje cells, and this pattern of expression was largely similar to that observed in neognathous birds. For example, all Purkinje cells in the lingular (lobule I) and nodular (lobule X) regions were ZII+, and there were 4 pairs of ZII+/-stripes in the anterior region (lobules II-V). In

more »

... trast to neognaths, however, ZII was expressed in lobules VI-VII as a series of sagittal stripes in the tinamou. Also unlike in neognaths, stripes were absent in lobule IXab, and all Purkinje cells expressed ZII in the tinamou. The differences in ZII expression between the tinamou and neognaths could reflect behavior, but the general similarity of the expression patterns across all bird species suggests that ZII stripes evolved early in the avian phylogenetic tree.