Inferring Adaptive Nature of Major Histocompatibility Complex (MHC) Polymorphism from Single Nucleotide Substitutions in Asian Sockeye Salmon Populations: II. Factors Determining Onne-DAB Gene Variability in the Kamchatka River Basin

Abstract

Variability of the Onne-DAB gene is examined using two single nucleotide polymorphisms (SNP) (One_MHC2_190v2 and One_MHC2_251v2) in datasets of early (spring) running sockeye salmon from tributaries and streams of the Kamchatka River basin. Differences in intrapopulation variability indices and interpopulation differentiation estimates in the datasets from different parts of the basin are most likely caused by action of different types of pathogen-induced selection in certain localities of the lake-river system. According to the results of factor analysis, two principal components (PC) are extracted. In sum, they explain 72% of general variability of genetic characteristics in the sockeye salmon datasets. A significant correlation between the second PC (33.4%) values and geographical distances from the corresponding tributary to Azabach’e Creek (Lake Azabach’e was selected as a reference point because it is the nursing lake for young sockeye from several tributaries and is located near the Kamchatka River mouth) is revealed. Moreover, a highly significant correlation between the second PC and prevalence of plerocercoid of Diphyllbothrium sp. in fish from the tributaries is derived.