Genetic Study of the Evens, an Ancient Human Population of Eastern Siberia

Three territorial subgroups of reindeer breeders, fishermen, and fur hunters living under conditions of partial isolation in remote parts of the Yakut ASSR, have been investigated with respect to polymorphic genetic systems. Analysis of covariance matrices containing allele frequencies in an array of 12 loci for a large sample of Evens, Nganasans, and reindeer Chukchi indicates that the genetic relationships support known phylogenetic, linguistic, and historical events

Modern genomics in studying the problems of human adaptation to climate in north Siberia

Актуальность: Коренные жители Сибири живут в экстремально суровых природных условиях на Земле, испытывая на себе длительное воздействие холода, сильных колебаний продолжительности светового дня и довольно ограниченного рациона питания. Очевидно, что успешное освоение человеком столь сложных для проживания территорий связано не только с культурной, но и с генетической адаптацией. Однако конкретные механизмы генетического приспособления к холодному климату, а также к диете с высоким содержанием животных жиров до сих пор остаются мало изученными. Цель исследования: Поиск маркеров полигенного отбора к климатическому стрессу в высоких северных широтах и пищевому рациону, основанному на богатой животными жирами пище. Материалы и методы: Исследование состояло из трёх этапов. На первом этапе в популяциях нганасан Таймыра (N=21) и якутов Республики Саха (N=21) выполнены отборочное полноэкзомное сканирование и полногеномный анализ однонуклеотидных замен (SNP). На втором этапе в «хвостах» эмпирических распределений выявлены гены-кандидаты, связанные с биологическими процессами и фенотипами, имеющими отношение к адаптации в циркумполярных группах. На третьем этапе лучшие кандидаты генотипированы в дополнительных популяциях Сибири, чтобы определить пространственное распределение частот аллелей и их ассоциации с климатическими переменными. Результаты: Были выявлены гены-кандидаты, из которых наибольший интерес представили гены PLA2G2A, PLIN1, ANGPTL8, вовлечённые в липидный метаболизм и связанные с бурой жировой тканью. В этих генах обнаружены несинонимичные замены, распространённость которых в северных популяциях указывает на вероятное воздействие естественного отбора. Заключение: Полученные результаты подтверждают гипотезу о том, что коренные популяции Сибири генетически адаптировались к жёсткой среде обитания путем отбора по нескольким генам, имеющим отношение к метаболизму жиров. Background: Indigenous people of north Siberia live in some of the harshest natural conditions on Earth, experiencing prolonged exposure to cold, large fluctuations in the length of daylight, and a limited diet. It is obvious that the successful occupation of such extremely difficult territories is connected not only with cultural but also with genetic adaptation. However, specific mechanisms of genetic adaptation to the cold climate and animal fat-rich diet still remain poorly understood. The aim of the study: To explore markers of polygenic selection for fat-rich diet and climate stress in the high northern latitudes. Materials and methods: The study consisted of three stages. At the first stage, we performed selection scans on whole exome and genome-wide single nucleotide polymorphism array data from the populations of Nganasans (N=21) and Yakuts (N=21). At the second stage, in the tails of empirical distributions, candidate genes associated with biological processes and phenotypes related to adaptation in circumpolar groups were revealed. At the third stage, the best candidates were genotyped in additional Siberian populations to determine the spatial distribution of allele frequencies and their associations with climatic variables. Results: We have identified several candidate genes, the most relevant being PLA2G2A, PLIN1, and ANGPTL8 genes involved in lipid metabolism and related to brown adipose tissue. Missense mutations in these genes exhibit spatial patterns consistent with selection for cold climate and/or diet. Conclusion: The results support the hypothesis that indigenous populations in Siberia have genetically adapted to harsh environments by selection on multiple genes related mostly to fat metabolism.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

A private allele ubiquitous in the Americas

The three-wave migration hypothesis of Greenberg et al. has permeated the genetic literature on the peopling of the Americas. Greenberg et al. proposed that Na-Dene, Aleut-Eskimo and Amerind are language phyla which represent separate migrations from Asia to the Americas. We show that a unique allele at autosomal microsatellite locus D9S1120 is present in all sampled North and South American populations, including the Na-Dene and Aleut-Eskimo, and in related Western Beringian groups, at an average frequency of 31.7%. This allele was not observed in any sampled putative Asian source populations or in other worldwide populations. Neither selection nor admixture explains the distribution of this regionally specific marker. The simplest explanation for the ubiquity of this allele across the Americas is that the same founding population contributed a large fraction of ancestry to all modern Native American populations

Buccal Micronucleus Cytome Assay for the Evaluation of Cytogenetic Status of Healthcare Professionals Contacting with Anti-Cancer Drugs

Abstract: Healthcare professionals of chemotherapy departments are in a regular contact with anticancer drugs that have genotoxic properties. The analysis of the cytogenetic status of healthcare professionals (54 individuals) was for the first time carried out using a new promising noninvasive method, buccal micronucleus cytome assay with the calculation of integral indices. The effect was estimated with different duration of exposure to chemotherapy drugs (after an employee’s vacation, one month after vacation, and before vacation). Statistically significant increases in almost all studied indices of cytogenetic damages, proliferation, and apoptosis as compared with the control group of office staff (47 individuals) were detected. Among healthcare professionals, an increase in the portion of individuals with an increased level of cytogenetic abnormalities with the maximum exposure duration from 24 to 38% (11% in the control) was established. Among cancer patients (9 individuals), the portion of individuals with a high level of cytogenetic abnormalities was 56% before the next course of chemotherapy and 87% after it. © 2022, Pleiades Publishing, Inc