Figure 1.

A model for recent Abp gene duplication events. (A) Partial map of Abp genes with arrows depicting genes (Abpa in blue, Abpbg in red); solid filled arrows are complete (potentially expressed) genes, while open arrows are putative pseudogenes (modified from [41]). <Abpbg-Abpa > modules are numbered 7–19 above the linkage map. Two duplications are depicted: 1) a large block of genes that duplicated to create the products underlined in green and orange; 2) those paralogs/modules designated X, Y and Z in the block on the right created products that are underlined in orange (14-31-15) and blue (16-32-17). The center portion of the Abp gene region created by these two duplications is shown as “Final Product” at the bottom of (A). (B) A phylogeny of the genes in the two duplications shown in A (modified from [40]). The partial Abp phylogeny (panel B) was modified from Laukaitis et al. [40], who produced an NJ phylogeny of intron 2 from rodent Abpa genes (their Figure 3, yellow clade at the top of the figure). The Abp branches derived from the mouse genome (labeled B6) were retained and the other branches removed. Paralog products are in a typeface color matching the bars that designate their places in the duplications and age estimates in Panel A. The age estimates of the duplications calculated by Laukaitis et al. [40] were also retained and are shown in red typeface.