Cluster of large gene family members in the middle of TcChr33. The region from ~0.2 Mb to 0.5 Mb contains mostly gene family members (non-blue "Gene Features"), while on either side of the region are "core" regions with either hypothetical genes or those with an assigned putative function (light and dark blue "Gene Features"). The large number of spanning BAC clones linking the core regions and the cluster of gene family members substantiates the organization. However, it should be noted that these homologous chromosomes are likely different sizes. The BAC clones on the "S" chromosome that span the 120 kb gap in the gene family rich region (connected by dashed lines) are too long for the BAC libraries as shown (TARBAC: blue, avg. length 75 kb, EPIFOS: green, avg. length 35 kb). Alignment of the homologous chromosomes is a visual aid to maintain allelic synteny only.