The principal directions and factors determining the variability of CYTB amino acid sequences in mountain voles (Alticola, Rodentia, Arvicolinae)
V. Yu. KOVALEVA1, I. V. MOROLDOEV1, Yu. N. LITVINOV1, K. V. EFIMOV2, V. M. EFIMOV3,4
1Institute of Systematics and Ecology of Animals of SB RAS, Novosibirsk, Russia
2Higher School of Economics, Moscow, Russia
3Tomsk State University, Tomsk, Russia
4Novosibirsk State University, Novosibirsk, Russia
Keywords: CYTB, amino acid sequences, principal components, physicochemical properties, evolutionary rank, environmental factors, Alticola
Abstract
A statistical analysis of the variability in the amino acid composition of the mitochondrial protein CYTB of Asian mountain voles of the genus Alticola was carried out. Sequences (N = 36; 380 a. a.) were taken from GenBank along with accompanying information about their geographical location. The frequencies of amino acids for each sequence and the matrix of squared Euclidean distances between them were calculated, from which the principal components (PC) were calculated using the principal coordinate method. In the space of the first two PCs (Σλ = 76.89 %), all sequences are grouped according to their species, forming the East Siberian (A. strelzowi, A. olchonensis, A. semicanus, A. tuvinicus), southern (A. stracheyi, A. argentatus, A. albicaudus, A. stoliczkanus, A. barakshin) and the northeastern group (A. lemminus, A. macrotis). Mutational pressure in the PC1 direction leads to a change in the frequencies of Met, Gly, Ile → Ala, Thr, which strongly correlates with a large subset of AA indices and the average evolutionary rank of CYTB sequences (N = 362 with p-value < 0.01 taking into account multiple comparisons according to Bonferroni). In the PC2 direction, the frequencies Val, Phe → Leu change. This direction reveals significant correlations with latitude, altitude, 21 climatic variables of vole habitats and 54 AA indices.
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