title: [Human hemoglobin: polymorphism, neutrality of variants, evolutionary aspect].
abstract: Integrated analysis of the polymorphism of human hemoglobin has been made using populational genetics, hematological, physiological, protein chemistry and molecular biology data. The known variants of human hemoglobin are conventionally classified as "widely common", "less common" and "rare", depending on their contribution to polymorphism. The importance of homeostasis and compensatory reactions for maintaining the resistance of the human body against mutant hemoglobins is emphasized. Hb D Punjab and Hb O Arab being relatively neutral, the genetic structure of populations may restrict their distribution. A hypothesis is put forward concerning the possible role of an increased local conformational mobility of protein in creating neutral protein variants. It is proposed to discriminate between truly neutral and pseudoneutral protein variants. In case of possible changes in the genetic and environmental factors, the former are not subject to selection, while the latter may be. Contribution to neutral evolution can be made only by truly neutral variants. In a compensated heterozygotic state the truly neutral and pseudoneutral variants may give rise to new functions and adaptively valuable properties in protein. The evolution of proteins is believed to proceed from a stage which is consistent with M. Kimura's concept of neutrality of protein polymorphism toward a stage which is consistent with the concept of selectionism. It is concluded, that the currently observed degree of polymorphism of human hemoglobin corresponds to the present stage of molecular evolution of the protein.
mesh_terms: D005075:Biological Evolution; D005828:Genetics, Population; D006454:Hemoglobins / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D009154:Mutation; D011110:Polymorphism, Genetic
chemical_list: D006454:Hemoglobins; D006455:Hemoglobins, Abnormal; C026237:hemoglobin D Punjab; C032031:hemoglobin Arab
vernacular_title: Gemoglobin cheloveka: polimorfizm, neĭtral'nost' variantov, évoliutsionnyĭ aspekt.