Anopheles beklemishevi Stegnii et Kabanova is a malaria mosquito and member of the Maculipennis group inhabiting in Palearctic. Its distribution area is the northernmost among malaria mosquitoes of Eurasia and covers the harshest climatic zones of Western and Eastern Siberia as well as northern Europe. The genetic mechanisms of cold resistance of Anopheles mosquitoes may be related to adaptive inversion polymorphism. An. beklemishevi is a one of the rare species of malaria mosquitoes, in which inversions in X chromosome are widespread in natural populations. Until now polymorphic inversions X1 and X2 have been found, according to the literature and our own observations, only in heterozygous state. This could be seen as a Hardy-Weinberg disequilibrium. Because of peculiarities of localization of inversions, the analysis of the order of chromosomal banding of polytene chromosomes does not allow reliably detect inverted homozygous.

The material for the study were samples of Anopheles mosquitoes larvae had been caught in natural reservoirs in Siberia during the period from 2019 to 2021. The geography of samples includes specimens from Yamalo-Nenets Autonomous Okrug (YaNAO), Khanty-Mansi Autonomous Okrug (KhMAO), Krasnoyarsk Krai (KK), Tomsk Oblast (TO) and Altay Republic.

As the result, it has been identified 480 larvae of An. beklemishevi from 8 natural populations. The distance between the northernmost (village Shuryshkary) and southernmost one (village Ozernoye) was almost 2000 kilometers in a straight line. In a car this way will be approximately 3100 kilometers. Usually, the larvae of An. beklemishevi inhabits with An. messeae and An. daciae together, but in the north and in the highlands as in the early-summer period, mainly individuals only of this species can be found.