Phenotypic analysis of Atlantic cod hemoglobin chains using a combination of top-down and bottom-up mass spectrometric approaches

Amino acid sequence information of both α- and β-chains of hemoglobin collected from Atlantic cod was obtained using a combination of mass spectrometry-based top-down and bottom-up approaches. Although complete sequencing is a very challenging undertaking due to the high degree of phenotypic variation, we were able to obtain between 38%, 28%, 46%, and 18% sequence coverage for the α-1-globin, α-2-globin, β-1-globin, and β-2-globin, respectively. The results of this work provide some evidence that the hemoglobin of Atlantic cod caught off the New England shoreline in the United States show genotypic/phenotypic variation from the hemoglobin of the same species caught off the coast of Norway. Though full coverage of the sequences was not accomplished, this work demonstrates the importance of further study to catalog the phenotypic variation of the American populations of Atlantic cod.