Blood type systems are defined by the single allele that encodes the antigens (as you point out, sometimes multiple antigens per allele). This table shows all o

Blood type systems are defined by the single allele that encodes the antigens (as you point out, sometimes multiple antigens per allele). This table shows all of the different blood type systems, https://www.isbtweb.org/resource/tableofbloodgroupsystems.html https://www.isbtweb.org/resource/tableofbloodgroupsystems.ht..., and the chromosomal location of the respective allele.