Haplogroup Distribution Research Articles

Y chromosome sequencing data suggest dual paths of haplogroup N1a1 into Finland.

The paternally inherited Y chromosome is highly informative of genetic ancestry, therefore making it useful in studies of population history. In Finland, two Y-chromosomal haplogroups reveal the major substructure of the population: N1a1 enriched in the northeast and I1a in the southwest, suggested to reflect eastern and western ancestry contributions to the population. Yet, beyond these major Y-chromosomal lineages, the distribution of finer-scale Y-chromosomal variation has not been assessed in Finland. Here, we provide the most comprehensive Y-chromosomal study among the Finns to date, exploiting sequences for 1802 geographically mapped Finnish Y chromosomes from the FINRISK project. We assessed the distribution of common Y-chromosomal haplogroups (frequency ≥1%) throughout 19 Finnish regions and compared the autosomal genetic backgrounds of the Y-chromosomal haplogroups. With such high-resolution data, we were able to find previously unreported sublineages and resolve phylogenetic relationships within haplogroups N1a1 (64%), I1a (25%), R1a (4.3%), and R1b (4.8%). We further find novel geographical enrichment patterns among these Y-chromosomal haplogroups, most notably observed for haplogroup N1a1 dividing into two lineages with differing distributions. While sublineage N-Z1934 (42%) followed a northeastern enrichment pattern observed for all N1a1 carriers in general, sublineage N-VL29 (22%) displayed an enrichment in the southwest. Further, the carriers of N-VL29 showed a higher proportion of southwestern autosomal ancestry compared to carriers of N-Z1934. Collectively, these results point to distinct demographics within haplogroup N1a1, possibly induced by two distinct arrival routes into Finland. Overall, our study suggests a more complex genetic population history for Finns than previously proposed.

Phylogeography of Y-chromosome haplogroup I-P37.2 in Serbian population groups originating from distinct parts of the Balkan Peninsula

Genetic structure of the contemporary Serbian population was shaped by a long history of turbulent historical and demographical events. The most important migrations of Serbs towards present day Serbia, in the recent history, occurred between the 15th to the 18th century from the regions of Old Herzegovina and Kosovo and Metohija. Previous haplogroup analysis revealed wide spectrum of main haplogroups, among which haplogroup I-P37.2 was the most frequent one in Serbian population groups originating from the Balkan Peninsula. Within this study 464 Serbian males samples from three geographical regions in the Balkan Peninsula inhabited by Serbs: present-day Serbia, regions of Old Herzegovina and Kosovo and Metohija, previously classified as haplogroup I-P37.2, were genotyped using the 22 Y-single nucleotide polymorphisms (Y-SNPs) in order to determine deeper phylogenetic and phylogeographic analysis of haplogroup I-P37.2. Based on SNP typing all samples in the Old Herzegovina and present-day Serbia dataset and 122 out of 128 samples from Kosovo and Metohija were assigned to haplogroup I-L621. Further SNP typing revealed very similar haplogroup distribution in all datasets, with the predominant haplogroup being I-PH908, followed by haplogroup I-Z17855. Analysis within haplogroup I-PH908 distinguished haplogroup I-FT14506 as the most frequent in the Kosovo and Metohija dataset, while haplogroup I-FT16449 was the most frequent in the Old Herzegovina dataset. In the present-day Serbia dataset, occurrence of haplogroups I-FT14506 and I-FT16449 was almost equal, comprising 40.2 % and 34.4 %, respectively. Low level of differentiation, within haplogroup I-PH908, was detected between all datasets, with the lowest one detected between present-day Serbia and Old Herzegovina datasets and highest one between Kosovo and Metohija and Old Herzegovina datasets. Furthermore, median-joining network analysis and shared haplotypes statistics revealed closer genetic relationship between Old Herzegovina and present-day Serbia haplotypes. Results obtained within this study support the thesis that migrations from historical region of Old Herzegovina and geographical region of Kosovo and Metohija, had great contribution on the present-day Serbian population genetic structure. Furthermore, here presented results, gave insight into geographic distribution of detected haplogroups I-Z17855, I-Y4460, I-PH908, I-Y5596, I-Y4882, I-FT14506, I-FT16449 and I-A5913 and analyzed SNPs, enabling further improvement of the geographic resolution of paternal ancestry inference.

Mitochondrial genome variants associated with amyotrophic lateral sclerosis and their haplogroup distribution.

Amyotrophic lateral sclerosis (ALS) may be familial or sporadic, and twin studies have revealed that even sporadic forms have a significant genetic component. Variants in 55 nuclear genes have been associated with ALS and although mitochondrial dysfunction is observed in ALS, variants in mitochondrial genomes (mitogenomes) have not yet been tested for association with ALS. The aim of this study was to determine whether mitogenome variants are associated with ALS. We conducted a genome-wide association study (GWAS) in mitogenomes of 1965 ALS patients and 2547 controls. We identified 51 mitogenome variants with p values <10-7, of which 13 had odds ratios (ORs) >1, in genes RNR1, ND1, CO1, CO3, ND5, ND6, and CYB, while 38 variants had OR <1 in genes RNR1, RNA2, ND1, ND2, CO2, ATP8, ATP6, CO3, ND3, ND4, ND5, ND6, and CYB. The frequencies of haplogroups H, U, and L, the most frequent in our ALS data set, were the same in different onset sites (bulbar, limb, spinal, and axial). Also, intra-haplogroup GWAS revealed unique ALS-associated variants in haplogroups L and U. Our study shows that mitogenome single nucleotide variants (SNVs) are associated with ALS and suggests that these SNVs could be included in routine genetic testing for ALS and that mitochondrial replacement therapy has the potential to serve as a basis for ALS treatment.

Genetic Diversity and Haplogroup Distribution of Three Ethnic Groups Tay, Thai, and Nung

The mitochondrial genome, with outstanding characteristics such as maternal inheritance, non-recombination and high mutation rate, is of great importance in population genetics and evolution research. To study the genetic diversity and the distribution of haplogroups of the Tai – Kadai language group, blood samples of 108 men from three ethnic groups Tay, Thai and Nung were collected. Total DNA extracted from blood samples was used for library preparation and whole mitochondrial genome sequencing using NGS. Comparing the obtained mitochondrial genome sequence with the RSRS (Reconstructed Sapiens Reference sequence) from Genbank (NC_012920) revealed 3929 distinct variants in 108 individuals with 1663 variants in the Tay ethnic group, 905 variants in the Thai ethnic group and 1361 variants in the Nung ethnic group. Nucleotide diversity (π) and haplotype were highest in the Thai ethnic group, being 0.0023 and 0.989, respectively. The genetic distances between each ethnic group pair (Tay-Nung, Tay-Thai and Thai-Nung), as shown by the FST values, were 0.03101; 0.00447 and 0.03282, respectively. Haplogroup analysis showed that 108 studied individuals belonged to 33 different haplogroups, belonging to 2 groups of haplogroups M and N. The most frequent haplogroups in Tay Thai and Nung were B4, F1 and M7, respectively. The results of this study show that although belonging to the same Tai - Kadai language family, the mitochondrial genomes among the three ethnic groups Tay, Thai, and Nung still have notable differences.

Paternal genetic structure analysis of the modern Han populations based on Y-SNP and Y-STR.

The Han populations represent the largest ethnic group in China. Previous studies have primarily focused on investigating their genetic origins, migration and integration, as well as paternal genetic relationships within specific regional Han populations. However, a comprehensive analysis of the global paternal genetic structure of Han populations is lacking. In this study, we performed Y-chromosome sequencing on 362 unrelated male samples from Chinese Han individuals collected from Qinghai, Sichuan and Liaoning provinces. We then integrated relevant data from reported studies. Our final dataset comprised 1830 samples from 16 Han populations across 15 provinces in China, encompassing information on 89 Y-SNPs and 16 Y-STRs. Statistical analyses were conducted to assess Y-STR haplotype diversity (HD) and Y-SNP haplogroup frequencies. Additionally, we employed principal component analysis (PCA), phylogenetic tree and haplotype network to explore genetic differentiation within Han populations and the genetic relationships between Han populations and ethnic minorities surrounding them. Our results demonstrated that the O-M175 haplogroup represents the predominant paternal lineage in Han populations, with frequencies ranging from 60.53% (Qinghai Han) to 92.7% (Guangdong Han). Moreover, the subclades downstream of O-M175 showed distinct regional variations in their distribution patterns. The O2-M122 haplogroup was prevalent in all Han populations and demonstrated a gradual decline in frequency from north to south. Conversely, the distribution frequency of the O1b-M268 haplogroup decreased from south to north, particularly showed significant presence among Han populations in the Lingnan region. Haplogroup O1a-M119 distributed more frequently in the central Han populations. Our findings revealed that Chinese Han populations can be categorized into three subgroups: northern, central, and southern. Notably, there were significant differences among Han in Qinghai and other regions. Regarding the genetic relationships between Han populations and surrounding ethnic minorities, we observed a closer genetic affinity between different Han populations, but northern Han demonstrated a stronger relationship with the Hui ethnic group, while southern Han exhibited a closer connection with the Gelao and Li ethnic groups. In summary, this study presented a systematic analysis of haplogroup distribution, genetic substructure of Han populations and genetic relationships between Han populations and surrounding ethnic minorities based on 89 Y-SNPs and 16 Y-STRs systematically. Our research supplemented valuable insights into population genetics and forensic genetics, and provided data support for the forensic application of Y chromosome. The integration of Y-SNP haplogroups with Y-STR haplotypes offers enhanced understanding of the genetic substructure within Han populations, which holds significance for both population genetics research and forensic science applications.

Analysis of maternal genetic structure of mitochondrial DNA control region from Tai-Kadai-speaking Buyei population in southwestern China

BackgroundEven though the Buyei are a recognised ethnic group in southwestern China, there hasn’t been much work done on forensic population genetics, notably using mitochondrial DNA. The sequences and haplogroups of mitochondrial DNA control regions of the Buyei peoples were studied to provide support for the establishment of a reference database for forensic DNA analysis in East Asia.Methods and resultsThe mitochondrial DNA control region sequences of 200 Buyei individuals in Guizhou were investigated. The haplotype frequencies and haplogroup distribution of the Buyei nationality in Guizhou were calculated. At the same time, the paired Fst values of the study population and other populations around the world were computed, to explore their genetic polymorphism and population relationship. A total of 179 haplotypes were detected in the Buyei population, with frequencies of 0.005–0.015. All haplotypes were assigned to 89 different haplogroups. The haplotype diversity and random matching probability were 0.999283 and 0.0063, respectively. The paired Fst genetic distances and correlation p-values among the 54 populations revealed that the Guizhou Buyei was most closely related to the Henan Han and the Guizhou Miao, and closer to the Hazara population in Pakistan and the Chiang Mai population.ConclusionsThe study of mitochondrial DNA based on the maternal genetic structure of the Buyei nationality in Guizhou will benefit the establishment of an East Asian forensic DNA reference database and provide a reference for anthropological research in the future.

Y chromosome haplogroups are associated with birth size in Japanese men.

The Y chromosome is classified into haplogroups (A-T) based on a combination of several DNA polymorphisms. Japanese men are mainly classified into haplogroups C, D, and O, which have been further subdivided. The distribution of Y-chromosome haplogroups varies by ethnicity. The phylogenetic age, origin, and migration also differ. I hypothesized that Y chromosome haplogroups may be associated with height and/or weight at birth. An association analysis of height and weight at birth with Y chromosome haplogroups was performed in 288 Japanese men. Men belonging to haplogroup O1b2 were significantly associated with short stature at birth (beta = －1.88, standard error (SE) = 0.55, P = 0.00076), and those belonging to D1a2a-12f2b were significantly associated with increased birth weight (beta = 174, SE = 64, P = 0.0069). Y chromosome haplogroups are associated with physical birth characteristics in modern Japanese men. J. Med. Invest. 71 : 129-133, February, 2024.

The maternal genetic origin and diversity of the extant populations of the Ladakh region in India

Ladakh lies at a strategic location between the Indus River valley and the Hindu Khush Mountains, which makes the “Land of high passes” one of the major routes of movement. Through the years the region has faced multi-layered cultural movements, genetic assimilation and demographic changes. The initial settlement in the years goes back to the early Neolithic age and still continues despite its harsh, unhospitable and cold climate. Previous studies mostly covered the patrilineal markers of the region and an in-depth study lacked to represent the matrilineal ancestry and possible genetic inflow in the region. Hence, our current study first time generated complete mitogenomes of 108 unrelated individuals from Ladakh belonging to three population groups namely, Changpa (n = 38), Brokpa (n = 32) and Monpa (n = 38). In the in-depth analysis, we found that the mitogenome of the three Ladakhi groups are highly diverse in terms of maternal haplogroup distribution carrying lineages specific to East Asia (M9a), Tibbet (A21) and South Asia (M3, M30, U2). In our analysis we found that Changpa and Monpa probably have shared maternal ancestry compared to Brokpa, which is very distinct and also later suffered possible historical Bottleneck. Bayesian evolutionary and Network analysis indicates more ancient maternal lineage of Changpa and Monpa in terms of M9a haplotypes, but they also share some genetic history with Tibeto-Burman speakers in past. These findings conclusively indicate possible matrilineal genetic inflow in Ladakh from three directions, primarily from East Asia or South East Asia during post-glacial, West Eurasia and also from South Asia.

Genetic Affinities and Adaptation of the South-West Coast Populations of India.

Evolutionary event has not only altered the genetic structure of human populations but also associated with social and cultural transformation. South Asian populations were the result of migration and admixture of genetically and culturally diverse groups. Most of the genetic studies pointed to large-scale admixture events between Ancestral North Indian (ANI) and Ancestral South Indian (ASI) groups, also additional layers of recent admixture. In the present study, we have analyzed 213 individuals inhabited in South-west coast India with traditional warriors and feudal lord status and historically associated with migratory events from North/North West India and possible admixture with West Eurasian populations, whose genetic links are still missing. Analysis of autosomal Single Nucleotide Polymorphism (SNP) markers suggests that these groups possibly derived their ancestry from some groups of North West India having additional Middle Eastern genetic components. Higher distribution of West Eurasian mitochondrial haplogroups also points to female-mediated admixture. Estimation of Effective Migration Surface (EEMS) analysis indicates Central India and Godavari basin as a crucial transition zone for population migration from North and North West India to South-west coastal India. Selection screen using 3 distinct outlier-based approaches revealed genetic signatures related to Immunity and protection from Viral infections. Thus, our study suggests that the South-west coastal groups with traditional warriors and feudal lords' status are of a distinct lineage compared to Dravidian and Gangetic plain Indo-Europeans and are remnants of very early migrations from North West India following the Godavari basin to Karnataka and Kerala.

Unraveling the mitochondrial phylogenetic landscape of Thailand reveals complex admixture and demographic dynamics

The evolutionary dynamics of mitochondrial DNA within the Thai population were comprehensively explored with a specific focus on the influence of South Asian admixture. A total of 166 samples were collected through randomized sampling, ensuring a diverse representation. Our findings unveil substantial genetic and haplogroup diversity within the Thai population. We have identified 164 haplotypes categorized into 97 haplogroups, with a notable inclusion of 20 novel haplogroups. The distribution of haplogroups exhibited variations across different populations and countries. The central Thai population displayed a high diversity of haplogroups from both the M and N clades. Maternal lineage affinities were discerned between several Mainland Southeast Asia (MSEA) and South Asian populations, implying ancestral genetic connections and a substantial influence of South Asian women in establishing these relationships. f4-statistics indicates the presence of a Tibeto-Burman genetic component within the Mon population from Thailand. New findings demonstrate two phases of population expansion occurring 22,000–26,000 and 2500–3800 years ago, coinciding with the Last Glacial Maximum, and Neolithic demographic transition, respectively. This research significantly enhances our understanding of the maternal genetic history of Thailand and MSEA, emphasizing the influence of South Asian admixture. Moreover, it underscores the critical role of prior information, such as mutation rates, within the Bayesian framework for accurate estimation of coalescence times and inferring demographic history.

Distribution Peculiarities of Y-Chromosome Haplogroups in the Population of St. Petersburg in Connection with the Problem of Creation Reference Data Bases

In the sample of male residents of St. Petersburg, Y-chromosome haplogroups were determined by genotyping 18 STR Y-chromosome (DYS389I, DYS389II, DYS390, DYS19, DYS385A, DYS385B, DYS456, DYS437, DYS438, DYS447, DYS448, DYS449, DYS391, DYS392, DYS393, DYS439, DYS635 and DYS576) and data on genetic demography were collected by means of a questionnaire. The distribution of Y-chromosome haplogroups in St. Petersburg residents generally corresponds to the published data on Russian gene pool, with the most frequent haplogroups R1a, R1b, E1b1b1, N, T, I1, I2, J1 and J2, and with the predominance of haplogroup R1a. The presence of “southern by origin” haplogroups (C3, G2a, G2c, J1, J2, L, O2, O3, Q, R2 and T) entering the megalopolis with a flow of migrants, with a total frequency of 16% (in Moscow – 18.1%) was noted. A comparative analysis of the frequency distributions of Y-chromosome haplogroups in residents of St. Petersburg and Moscow revealed statistically significant differences in the frequency of haplogroup E1b1b1, and differences in the ratio of I1 and I2, determined by geographic position. Based on the survey data, a sample of Russian men who had no ancestors of another ethnicity in the male line in the two previous generations was formed. Significant differences in the frequency of “southern-origin” haplogroups were established between the initial sample of residents of St. Petersburg (16%) and the sample of men with Russian ancestors in two previous generations (4.1%). The obtained result confirms the spectrum of haplogroups of “southern origin” as penetrating into the gene pool of the population of a megalopolis with migrant flows and indicates the need for genetic and demographic questionnaires when forming reference databases for a megalopolis, as well as for their timely updating due to changes in the gene pool under the influence of migration.

The maternal ancestry of the Kavaratti islanders and the last glacial maximum aftermath.

The prehistoric human settlement of the Lakshadweep islands remains a mystery for various reasons. Uncertainty about the existence of indigenous tribes in these islands and the lack of folklore records present major obstacles to the reconstruction of Lakshadweep ancestry. However, with extant population data, we seek to understand the maternal ancestry of theKavaratti islanders. Mitochondrial control region variation analysis of 80 individuals from this island shows maternal links with the populations in the northwestern region of the South Asian mainland. The founder clade R30b2, observed in the Kavaratti islanders, is so far present only in the Scheduled Castes from the Punjab region, Jat Sikhs and Nairs. All other mainland populations carry basal R30 or R30a subclades. The presence of a specific Uralic U4 lineage in our samples, in addition to the Indo-European affinity observed in the phylogeny tree, substantiates a northwestern maternal ancestry of the Kavaratti islanders and implies an ancestral admixture with early humans in the Near East at the time of the last glacial maximum (LGM). Based on our Bayesian analysis, we furthermore propose that a group bearing mostly R30b2 during the LGM recovery, moved eastward and southward, where they received Indian-specific M haplogroups. Hence, the maternal ancestry of the Kavaratti islanders is evidently a consequence of the demographic changes in the northwestern region of the Indian subcontinent caused by the Last Glacial Maximum. The haplogroup distribution pattern and nucleotide sequence data produced in this study will enrich the forensic database of the Lakshadweep islands.

Genetic analysis of 42 Y-STR loci in Han and Manchu populations from the three northeastern provinces in China

BackgroundY-STR polymorphisms are useful in tracing genealogy and understanding human origins and migration history. This study aimed to fill a knowledge gap in the genetic diversity, structure, and haplogroup distribution of the Han and Manchu populations from the three northeastern provinces in China (Liaoning, Jilin, and Heilongjiang).MethodsA total of 1,048 blood samples were collected from unrelated males residing in Dalian. Genotyping was performed using the AGCU Y37 + 5 Amplification Kit, and the genotype data were analyzed to determine allele and haplotype frequencies, genetic and haplotype diversity, discrimination capacity, and haplotype match probability. Population pairwise genetic distances (Fst) were calculated to compare the genetic relationships among Han and Manchu populations from Northeast China and other 23 populations using 27 Yfiler Plus loci set. Multi-dimensional scaling and phylogenetic analysis were employed to visualize the genetic relationships among the 27 populations. Moreover, haplogroups were predicted based on 27 Yfiler Plus loci set.ResultsThe Han populations from Northeast China exhibited genetic affinities with both Han populations from the Central Plain and the Sichuan Qiang population, despite considerable geographical distances. Conversely, the Manchu population displayed a relatively large genetic distance from other populations. The haplogroup analysis revealed the prevalence of haplogroups E1b1b, O1b, O2, and Q in the studied populations, with variations observed among different ethnic groups.ConclusionThe study contributes to our understanding of genetic diversity and history of the Han and Manchu populations in Northeast China, the genetic relationships between populations, and the intricate processes of migration, intermarriage, and cultural integration that have shaped the region’s genetic landscape.

Ancient DNA reveals genetic admixture in China during tiger evolution.

The tiger (Panthera tigris) is a charismatic megafauna species that originated and diversified in Asia and probably experienced population contraction and expansion during the Pleistocene, resulting in low genetic diversity of modern tigers. However, little is known about patterns of genomic diversity in ancient populations. Here we generated whole-genome sequences from ancient or historical (100-10,000 yr old) specimens collected across mainland Asia, including a 10,600-yr-old Russian Far East specimen (RUSA21, 8× coverage) plus six ancient mitogenomes, 14 South China tigers (0.1-12×) and three Caspian tigers (4-8×). Admixture analysis showed that RUSA21 clustered within modern Northeast Asian phylogroups and partially derived from an extinct Late Pleistocene lineage. While some of the 8,000-10,000-yr-old Russian Far East mitogenomes are basal to all tigers, one 2,000-yr-old specimen resembles present Amur tigers. Phylogenomic analyses suggested that the Caspian tiger probably dispersed from an ancestral Northeast Asian population and experienced gene flow from southern Bengal tigers. Lastly, genome-wide monophyly supported the South China tiger as a distinct subspecies, albeit with mitochondrial paraphyly, hence resolving its longstanding taxonomic controversy. The distribution of mitochondrial haplogroups corroborated by biogeographical modelling suggested that Southwest China was a Late Pleistocene refugium for a relic basal lineage. As suitable habitat returned, admixture between divergent lineages of South China tigers took place in Eastern China, promoting the evolution of other northern subspecies. Altogether, our analysis of ancient genomes sheds light on the evolutionary history of tigers and supports the existence of nine modern subspecies.

Phylogeography of Limia vittata (Cyprinodontiformes: Poeciliidae): geographical distribution of mitochondrial haplotypes is comparable to other Cuban poeciliids

Abstract The genus Limia is endemic to the Greater Antilles with a single species in Cuba, Limia vittata, widespread in lowland ecosystems. The limited data available regarding its population structure suggest that its levels of intraspecific divergence are lower compared to other Cuban poeciliids. Furthermore, little is known about the dispersal pathways and demographic changes experienced by present-day populations. By analysing two mitochondrial markers and testing scenarios of dispersal and vicariance, we provide insights into the evolutionary history of L. vittata. Here, we show that this species is formed by three genetically differentiated and geographically delimited groups of populations. We also found moderate intraspecific divergence and a mtDNA pattern of high haplotype diversity and low nucleotide diversity which is consistent with a rapid demographic expansion. Our Bayesian analysis recovered dispersal from eastern to western Cuba as the most likely scenario explaining the current distribution of this species. Limia vittata exhibited a distinct regional distribution of haplogroups that corresponds to major core landmasses within Cuba, along with a signature of rapid population expansion during relatively recent palaeoclimatic changes that occurred during the formation of the archipelago. Similar phylogeographic patterns have been identified in other freshwater and terrestrial taxa on the island.

Insights on the Evolutionary History and Genetic Patterns of Octopus vulgaris Cuvier, 1797 in the Northeastern Atlantic Using Mitochondrial DNA.

Octopus vulgaris is one of the most harvested octopus species in the world. In the Iberian Peninsula, there are several small-scale fisheries that have a long-term tradition of harvesting octopus. The Asturias fleet (in Northern Spain) has an internationally recognized MSC label for its exploitation. Of concern, genetic assessments of exploited stocks are currently scarce, which could prevent the implementation of adequate managing strategies. We use two mitochondrial regions (cytochrome oxidase subunit 1 and control region) to analyze the genetic status and evolutionary events that conditioned octopus populations' characteristics in the Northeastern Atlantic. A total of 90 individuals were sampled from three different localities in the Iberian Peninsula as well as a location in Macaronesia. Temporal genetic analyses on Asturias and Algarve populations were also performed. Results indicated the absence of fine spatial genetic structuring but showed the Canary Islands (in Macaronesia) as the most distinct population. Our analyses detected two distinct clades, already described in the literature, but, for the first time, we confirmed the presence of the α-southern haplogroup in the Northern Iberian Peninsula. This result indicates a more continuous cline for the distribution of these two haplogroups than previously reported. Temporal changes in the distribution of both haplogroups in contact zones were also detected.

Mitochondrial Genome Variation in Polish Elite Athletes.

Energy efficiency is one of the fundamental athletic performance-affecting features of the cell and the organism as a whole. Mitochondrial DNA (mtDNA) variants and haplogroups have been linked to the successful practice of various sports, but despite numerous studies, understanding of the correlation is far from being comprehensive. In this study, the mtDNA sequence and copy number were determined for 99 outstanding Polish male athletes performing in power (n = 52) or endurance sports (n = 47) and 100 controls. The distribution of haplogroups, single nucleotide variant association, heteroplasmy, and mtDNA copy number were analyzed in the blood and saliva. We found no correlation between any haplogroup, single nucleotide variant, especially rare or non-synonymous ones, and athletic performance. Interestingly, heteroplasmy was less frequent in the study group, especially in endurance athletes. We observed a lower mtDNA copy number in both power and endurance athletes compared to controls. This could result from an inactivity of compensatory mechanisms activated by disadvantageous variants present in the general population and indicates a favorable genetic makeup of the athletes. The results emphasize a need for a more comprehensive analysis of the involvement of the mitochondrial genome in physical performance, combining nucleotide and copy number analysis in the context of nuclear gene variants.

Exploring the legacy of African and Indigenous Caribbean admixture in Puerto Rico.

From an anthropological genetic perspective, little is known about the ethnogenesis of African descendants in Puerto Rico. Furthermore, historical interactions between Indigenous Caribbean and African descendant peoples that may be reflected in the ancestry of contemporary populations are understudied. Given this dearth of genetic research and the precedence for Afro-Indigenous interactions documented by historical, archeological, and other lines of evidence, we sought to assess the biogeographic origins of African descendant Puerto Ricans and to query the potential for Indigenous ancestry within this community. Saliva samples were collected from 58 self-identified African descendant Puerto Ricans residing in Puerto Rico. We sequenced whole mitochondrial genomes and genotyped Y chromosome haplogroups for each male individual (n = 25). Summary statistics, comparative analyses, and network analysis were used to assess diversity and variation in haplogroup distribution between the sample and comparative populations. As indicated by mitochondrial haplogroups, 66% had African, 5% had European, and 29% had Indigenous American matrilines. Along the Y chromosome, 52% had African, 28% had Western European, 16% had Eurasian, and, notably, 4% had Indigenous American patrilines. Both mitochondrial and Y chromosome haplogroup frequencies were significantly different from several comparative populations. Biogeographic origins are consistent with historical accounts of African, Indigenous American, and European ancestry. However, this first report of Indigenous American paternal ancestry in Puerto Rico suggests distinctive features within African descendant communities on the island. Future studies expanding sampling and incorporating higher resolution genetic markers are necessary to more fully understand African descendant history in Puerto Rico.

Alzheimer's disease: the hypotheses, known and unknown connections between UV-radiation, mtDNA haplotypes and life span - a review.

Alzheimer's disease (AD) is the most common neurodegenerative disease with controversial etiology. One theory claims that AD is due to brain aging affecting mainly the functions of mitochondria, therefore, the factors leading to mitochondrial ageing should lead to the development of Alzheimer's disease. Another theory is that different mitochondrial DNA haplogroups can be predisposition for the onset of the condition. Here we focused on the possible connection between AD and UV radiation using the data on the monthly UV index in Europe, its correlation with mortality rate due to AD and mitochondrial DNA haplogroups distribution. If a link between the two theories is proved, it will mean that UV radiation is a risk factor not only for skin cancer but also for a large group of neurodegenerative diseases amongst which is the Alzheimer's disease.

DNA barcode of tilapia fish fillet from the Brazilian market and a standardized COI haplotyping for molecular identification of Oreochromis spp. (Actinopterygii, Cichlidae)

The globalized production chains of fish products have been posing increasing difficulties in carrying out proper food control on any level. In case of species identification, morphological examinations that are usually efficient to identify entire fishes, fresh or frozen, fail when applied to fish derivative products, such as fillets or canned meat. In this study we evaluated the global distribution of tilapia COI haplotypes and haplogroups, contrasting diversity in native range and areas where Oreochromis spp. are regarded as introduced. Introduced areas showed a lower diversity of haplotypes comparatively to native areas, evidencing that cultures in different parts of the world originated from a few strains in Africa. Afterwards, evaluating COI diversity from tilapia fillets of the Brazilian market, we concluded that diversity in Brazilian cultures is similar to other countries where they were introduced, but it was highly heterogeneous among brands. Since part of the global movement on tilapia culture relies on crossbreeding of tilapia lineages, the difficulty in defining specific strains of tilapia through DNA barcodes is thought to increase. Our haplotyping system presents a practical form of molecular identification for tilapia products that may be useful in future taxonomic reviews. However, the estimated genetic diversity of Oreochromis through the COI marker does not necessarily reflect the diversity of species in the group, but rather the evolutionary history of this marker. Nevertheless, given the costs and feasibility of analyzing multiple markers, such as microsatellites, the current haplotyping standard is an improvement over the previous system.