Causes of the Excess of Frequency of SCH34 Mitotype in Population of Amur Sturgeon Acipenser schrenckii (Acipenseridae) Based on the Analysis of Complete Mitochondrial Genomes

Abstract

Most sturgeon species are endangered and included in various Red Lists. The study of the spectrum of allelic frequencies can help to assess and monitor the state of their populations. I sequenced nine complete mitogenomes of the Amur sturgeon representing seven different variants of the mtDNA control region, one of which (SCH34) has an unusually high frequency in the population, according to the previously obtained data. No selectively significant substitutions in the protein-coding nucleotide sequences or substitutions in other functional regions of the mitochondrial genome were found that would distinguish the SCH34 mitotype from others. One of the three mitogenomes with the same SCH34 mitotype of the control region had a nucleotide substitution outside of the region. The calculated minimum evolutionary age of the SCH34 mitotype is approximately 4500–5400 years. The high frequency of SCH34 and mitotypes close to it (originating from it and differing by one or two nucleotide positions) in the contemporary Amur sturgeon population could not have been caused by either selection or human activity and was most likely due to one of its isolated populations going through the low population phase (bottleneck) in the past.