Allotypes of IgG

A further division is into allotypes, which have smaller differences from one another and represent alternative forms. These are the result of allelic differences in the constant regions of the heavy chain genes. For example, in the domestic fowl, 14 allotypes of IgG-1 and five of the IgM-1 subclasses have been defined (Ch ng Benedict, 1981), and some of these... 

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