Hughes A L
Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.
J Mol Evol. 1996 Jul;43(1):4-10. doi: 10.1007/BF02352293.
The immunoglobulin-related chains of cell-surface receptors for the Fc region of immunoglobulins (FcepsilonRIalpha, FcgammaRI, FcgammaRII, and FcgammaRIIIalpha) are encoded by members of a gene family. Phylogenetic analysis of representative members of this family from mammals revealed that FcgammaRIIIalpha genes of human, mouse, and rat are not orthologous to one another in the region of the gene encoding the immunoglobulin C2-set domains. In phylogenetic trees of this region, FcgammaRIIIalpha and FcgammaRII clustered together. However, in trees based on both coding and noncoding regions 5' and 3' to the C2 domains, FcgammaRIIIalpha genes of human, mouse, and rat clustered together. This pattern of relationship is most easily explained as a result of two independent recombinational events occurring in the mouse and rat after these two species diverged, in each of which the exons encoding the C2 domains were donated to an FcgammaRIIIalpha gene by an FcgammaRII gene.
免疫球蛋白Fc区细胞表面受体的免疫球蛋白相关链（FcεRIα、FcγRI、FcγRII和FcγRIIIα）由一个基因家族的成员编码。对来自哺乳动物的该家族代表性成员进行系统发育分析发现，人、小鼠和大鼠的FcγRIIIα基因在编码免疫球蛋白C2-set结构域的基因区域彼此并非直系同源。在该区域的系统发育树中，FcγRIIIα和FcγRII聚集在一起。然而，在基于C2结构域5'和3'端编码区和非编码区构建的树中，人、小鼠和大鼠的FcγRIIIα基因聚集在一起。这种关系模式最容易解释为在小鼠和大鼠分化后，这两个物种各自发生了两次独立的重组事件，在每次事件中，编码C2结构域的外显子由一个FcγRII基因提供给一个FcγRIIIα基因。
