DNA polymorphism of dogs (Canis familiaris L.). I. Origin, distribution of dogs in the light of molecular biological data about their mitochondrial and nuclear genomes

Information is given on the size and organization of the mitochondrial and nuclear genomes of dogs, including information on polymorphisms of some loci used to clarify the phylogenetic relationships of wolves and the first dogs, including hypotheses about the places of domestication of ancient now extinct wolves and the dates of these events. It is noted that the introduction of molecular biological methods in archaeology has allowed to obtain the principally new data on ancient wolves and dogs. Based on mtDNA polymorphism and nuclear DNA polymorphism, migration routes of already domesticated dogs together with humans have been tracked. The previously existing points of view about the origin of the first dogs in Western Europe, as well as in East Asia, have been supplemented in recent years by assumptions about the appearance of the first proto-dogs in Siberia.

Cybrid Model Supports Mitochondrial Genetic Effect on Pig Litter Size

In pigs, mitochondrial DNA (mtDNA) polymorphism and the correlation to reproductive performance across breeds and individuals have been largely reported, however, experimental proof has never been provided. In this study, we analyzed 807 sows for correlation of total number born (TNB) and mitotype, which presented the maximum of 1.73 piglets for mtDNA contribution. Cybrid models representing different mitotypes were generated for identification of the mtDNA effect. Results indicated significant differences on cellular and molecular characteristics among cybrids, including energy metabolic traits, mtDNA copy numbers and transcriptions, mRNA and protein expressions on mitochondrial biogenesis genes and reproduction-related genes. Referring to mitotypes, the cybrids with prolific mitotypes presented significantly higher oxygen consumption rate (OCR) productions, mtDNA transcriptions and copy numbers than those with common mitotypes, while both mRNA and protein expressions of PPARA, TFAM, ER1, ER2, and ESRRG in prolific cybrids were significantly higher than those with common mitotypes. Cybrid models reflected the mtDNA effect on pig litter size, suggesting the potential application of mtDNA polymorphism in pig selection and breeding practices.

Mitochondrial genome variability in sudden cardiac death

Проведено исследование полиморфизма митохондриального генома и числа копий мтДНК в клетке при внезапной сердечной смерти (ВСС). Выявлено более низкое значение числа копий мтДНК в миокарде умерших ВСС. Анализ полиморфизма мтДНК показал более высокую частоту гаплогруппы Н1 в выборке ВСС, по сравнению с популяцией, а также более высокую частоту миссенс-варианта Ala177Thr в гене ATP6 у лиц, переживших остановку сердца. Результаты исследования указывают на связь полиморфизма мтДНК и числа копий мтДНК в клетке с риском внезапной сердечной смерти. We studied mitochondrial DNA polymorphism and mtDNA copy number in sudden cardiac death (SCD). In the SCD group, a lower mtDNA copy number was found in the myocardium. Analysis of mtDNA polymorphism revealed a higher frequency of H1 haplogroup in the SCD samples, compared with the population, as well as higher frequency of missense variant Ala177Thr in ATP6 gene in the group of cardiac arrest survivors. The results of the study suggest association of mtDNA polymorphism and mtDNA copy number with the risk of sudden cardiac death.

New Data on Phylogeography of the Boreal Owl Aegolius funereus in Eurasia

In the article the research’s results of phylogeography, genetic diversity, genetic structure and demographic characteristics of the Boreal Owl population in Eurasia are given. The first domain of control region of mtDNA is used as a genetic marker. The sample size was 59 specimens. The population of Boreal Owl is characteristic of high genetic diversity and it has signs of rapid expansion in the past as revealed by analysis of CR1 mtDNA polymorphism. Genetic differentiation between birds from the west and the east part of the species range is shown. The level of found population genetic differentiation isn’t high that can be explained by gene flow in the past and possible at the present time. We didn’t reveal any signs of genetic differentiation for Boreal Owl population according to subspecies (between A. f. funereus and A. f. pallens) which are distinguished for the studying area.

A Pro-Diabetogenic mtDNA Polymorphism in the Mitochondrial-Derived Peptide, MOTS-c

Type 2 Diabetes (T2D) is an emerging public health problem in Asia. An Asian mitochondrial DNA variation m.1382A>C (rs111033358) leads to a K14Q amino acid replacement in MOTS-c, an insulin sensitizing mitochondrial-derived peptide. Meta-analysis of three cohorts (n=27,527, J-MICC, MEC, and TMM) showed that males but not females with the C-allele exhibit a higher prevalence of T2D. Furthermore, in J-MICC, only males with the C-allele in the lowest tertile of physical activity increased their prevalence of T2D, demonstrating a kinesio-genomic interaction. High-fat fed, male mice injected with MOTS-c showed reduced weight and improved glucose tolerance, but not K14Q-MOTS-c treated mice. Like the human data, female mice were unaffected. Mechanistically, K14Q-MOTS-c leads to diminished insulin-sensitization in vitro. Thus, the m.1382A>C polymorphism is associated with susceptibility to T2D in men, possibly interacting with exercise, and contributing to the risk of T2D in sedentary males by reducing the activity of MOTS-c.

The study on the modifying role of mitochondrial DNA polymorphism in the Brugada syndrome manifestation

Background: Brugada syndrome is a hereditary disease with genetic and phenotypic variability characterized by a high risk for arrhythmia and sudden cardiac death. It is assumed that modifying genetic factors contribute to the variability of the phenotype. Mitochondrial DNA (mtDNA) polymorphism can be considered among such factors, since mitochondrial dysfunction, including that associated with mtDNA variants, can have an arrhythmogenic effect. Aim: To study possible association between mtDNA polymorphism with the phenotype in the Russian patients with Brugada syndrome. Materials and methods: We have studied mtDNA polymorphism in 36 Russian probands with Brugada syndrome. Common “European” haplogroups of mtDNA were assigned using sequencing of the hypervariable segment 1 in mtDNA D-loop. Results: In the study sample, the frequencies of the mtDNA haplogroups generally correspond to the distribution common for the Russian populations, except the J haplogroup, which was not found in the studied probands. The results contradict with previously published data on the J and T haplogroups as risk factors for Brugada syndrome manifestation. Conclusion: The study did not reveal the role of mtDNA polymorphism (J and T haplogroups) in the formation of the Brugada syndrome phenotype.

Association analysis of mitochondrial DNA polymorphisms with oocyte number in pigs

In pigs, correlations between mitochondrial (mt) DNA polymorphisms and economic traits have been widely reported across and within swine breeds. In fecundity studies, the number of oocytes within ovaries was highly correlated with litter size. However, the effect of mitochondrial polymorphisms on porcine oocyte number remained unclear. In this study, 181 porcine ovaries were collected to analyse the relationship between oocyte number and mtDNA polymorphisms. There were considerable differences in oocyte numbers among different ovaries from commercial pig breeds, ranging from 2.7×105 to 1.3×106. Mitochondrial D-loop sequencing discovered 53 polymorphic sites. Association analysis revealed that 13 variations were associated with the number of oocytes (P<0.05). A C323T polymorphism showed the largest value between the C and T carriers, which differed at 105 oocytes (P<0.05). The 53 polymorphic sites generated 45 haplotypes, which clustered into two haplogroups, A and B. Haplogroup A had a higher number of oocytes than Haplogroup B (P<0.05), whereas Haplotype H6 in Haplogroup A had the highest number of oocytes (~7.5×105) of all haplotypes studied (P<0.05). The results of this study highlight a correlation between mtDNA polymorphisms and oocyte number, and suggest the potential application of mtDNA polymorphism analyses in pig selection and breeding practices.