Structural Evidence for Heterogeneity of Two Hemoglobin α Chain Gene Loci in White-tailed Deer

• Published in: The Journal of biological chemistry 1972-11, Vol.247 (22), p.7320
• Main Authors: W. Jape Taylor, Caroline W. Easley, Hyram Kitchen
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X

An examination by tryptic peptide mapping and partial sequence determination of critical peptides of hemoglobins from white-tailed deer of known parentage established the presence of from one to three α chains in individual animals. Variations in the deer α chains occur at amino acid position number 20, at which ii α 1 contains lysine while i α 3 and i α 3 ' contain aspartic acid, and at position number 24, at which phenylalanine appears in ii α 1 and i α 3' and tyrosine appears in i α 3 . Either the i α 3' or the i α 3 chain may appear alone, but the ii α 1 chain is always linked with i α 3' . Duplication of a structural gene for the i α 3' chain, followed by a mutation at position number 20 to produce the ii α 1 gene, and a simple point mutation in the i α 3' gene at position number 24 to produce the i α 3 gene explain the findings with the smallest number of separate genetic events. The lysine-aspartic acid substitution in the duplicated gene product is less conservative than the phenylalanine-tyrosine mutation, supporting the theoretical concept that gene duplication permits a greater degree of evolutionary experimentation. Interestingly, the nonduplicated gene continues to persist singly in the population as well as in association with its mutant duplicate. This finding supports the concept that heterogeneity of the α chain gene loci may exist in man as well.