Human complement C4 locus is duplicated on some chromosomes.
D003181:Complement C4 / Q000235:genetics*; D005796:Genes; D008040:Genetic Linkage; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D008285:Major Histocompatibility Complex; D011110:Polymorphism, Genetic
D003181:Complement C4; D006680:HLA Antigens