title: Molecular evolution. How old is a polymorphism?
authors: J C
authors: JC
authors: Howard
mesh_terms: D000483:Alleles; D000818:Animals; D005075:Biological Evolution; D008285:Major Histocompatibility Complex; D011110:Polymorphism, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D013045:Species Specificity