Recombination of v-J-D gene segment of heavy chain ■■邒Ⅻ■邝圈鹽形丞 ，HLH2 Hn 041-12 Rearrament of DNA DH4 Cell DNA ■飞 ，H1LH2245 C Transcription DH4 Primary RNA Transcript J2 J3 J4 J5 mRNA J2 C Heavy Chainμ Heavy Chain Variable Region Diversity H chain diversity is generated by mechanisms quite similar to those previously described for L Chains.There are many V genes in the H chain gene family (perhaps as seen over30),which may encode the leader and the main region to the 5 residue There are also a number of functional J segments (dour in mice,an five in humans),which may encode part of the CDR3 and all of the last frame work region (FR4)described for the L chains.The process is somewhat more complex,since 10 to 20 short DNA segments,known as D,or diversity,segments are located between the H and J segments.D segments encode two to 14 amino acids in the hypervarible region,or complementary region 3(CDR3) and,therefore,are critically involved in determining the specificity of an antibody.Heavy Chain Variable Region Diversity H chain diversity is generated by mechanisms quite similar to those previously described for L Chains. There are many V genes in the H chain gene family (perhaps over 300), which may encode the leader and the main region to the 95 residue, as seen for L chains. There are also a number of functional J segments (dour in mice, and five in humans), which may encode part of the CDR3 and all of the last frame work region (FR4) described for the L chains. The process is somewhat more complex, since 10 to 20 short DNA segments, known as D, or diversity, segments are located between the H and J segments. D segments encode two to 14 amino acids in the hypervarible region, or complementary region 3 (CDR3), and, therefore, are critically involved in determining the specificity of an antibody