New Canary Islands Roman mediated settlement hypothesis deduced from coalescence ages of curated maternal indigenous lineages.

Numerous genetic studies have contributed to reconstructing the human history of the Canary Islands population. The recent use of new ancient DNA targeted enrichment and next-generation sequencing techniques on new Canary Islands samples have greatly improved these molecular results. However, the bulk of the available data is still provided by the classic mitochondrial DNA phylogenetic and phylogeographic studies carried out on the indigenous, historical, and extant human populations of the Canary Islands.

Digging into the admixture strata of current-day Canary Islanders based on mitogenomes.

The conquest of the Canary Islands by Europeans began at the beginning of the 15th century and culminated in 1496 with the surrender of the aborigines. The collapse of the aboriginal population during the conquest and the arrival of settlers caused a drastic change in the demographic composition of the archipelago. To shed light on this historical process, we analyzed 896 mitogenomes of current inhabitants from the seven main islands.

Human molecular evolutionary rate, time dependency and transient polymorphism effects viewed through ancient and modern mitochondrial DNA genomes.

Human evolutionary genetics gives a chronological framework to interpret the human history. It is based on the molecular clock hypothesis that suppose a straightforward relationship between the mutation rate and the substitution rate with independence of other factors as demography dynamics. Analyzing ancient and modern human complete mitochondrial genomes we show here that, along the time, the substitution rate can be significantly slower or faster than the average germline mutation rate confirming a time dependence effect mainly attributable to changes in the effective population size of the human populations, with an exponential growth in recent times.

Counterbalancing the time-dependent effect on the human mitochondrial DNA molecular clock.

Background: The molecular clock is an important genetic tool for estimating evolutionary timescales. However, the detection of a time-dependent effect on substitution rate estimates complicates its application. It has been suggested that demographic processes could be the main cause of this confounding effect.

Mitogenomes illuminate the origin and migration patterns of the indigenous people of the Canary Islands.

The Canary Islands' indigenous people have been the subject of substantial archaeological, anthropological, linguistic and genetic research pointing to a most probable North African Berber source. However, neither agreement about the exact point of origin nor a model for the indigenous colonization of the islands has been established. To shed light on these questions, we analyzed 48 ancient mitogenomes from 25 archaeological sites from the seven main islands.

Carriers of mitochondrial DNA macrohaplogroup L3 basal lineages migrated back to Africa from Asia around 70,000 years ago.

Background: The main unequivocal conclusion after three decades of phylogeographic mtDNA studies is the African origin of all extant modern humans. In addition, a southern coastal route has been argued for to explain the Eurasian colonization of these African pioneers. Based on the age of macrohaplogroup L3, from which all maternal Eurasian and the majority of African lineages originated, the out-of-Africa event has been dated around 60-70 kya.

Carriers of mitochondrial DNA macrohaplogroup R colonized Eurasia and Australasia from a southeast Asia core area.

Background: The colonization of Eurasia and Australasia by African modern humans has been explained, nearly unanimously, as the result of a quick southern coastal dispersal route through the Arabian Peninsula, the Indian subcontinent, and the Indochinese Peninsula, to reach Australia around 50 kya. The phylogeny and phylogeography of the major mitochondrial DNA Eurasian haplogroups M and N have played the main role in giving molecular genetics support to that scenario. However, using the same molecular tools, a northern route across central Asia has been invoked as an alternative that is more conciliatory with the fossil record of East Asia.

Carriers of human mitochondrial DNA macrohaplogroup M colonized India from southeastern Asia.

Background: From a mtDNA dominant perspective, the exit from Africa of modern humans to colonize Eurasia occurred once, around 60 kya, following a southern coastal route across Arabia and India to reach Australia short after. These pioneers carried with them the currently dominant Eurasian lineages M and N. Based also on mtDNA phylogenetic and phylogeographic grounds, some authors have proposed the coeval existence of a northern route across the Levant that brought mtDNA macrohaplogroup N to Australia.

Mitochondrial DNA haplogroup phylogeny of the dog: Proposal for a cladistic nomenclature.

Canis lupus familiaris mitochondrial DNA analysis has increased in recent years, not only for the purpose of deciphering dog domestication but also for forensic genetic studies or breed characterization. The resultant accumulation of data has increased the need for a normalized and phylogenetic-based nomenclature like those provided for human maternal lineages. Although a standardized classification has been proposed, haplotype names within clades have been assigned gradually without considering the evolutionary history of dog mtDNA.

Isolation and prominent aboriginal maternal legacy in the present-day population of La Gomera (Canary Islands).

The present-day population structure of La Gomera is outstanding in its high aboriginal heritage, the greatest in the Canary Islands. This was earlier confirmed by both mitochondrial DNA and autosomal analyses, although genetic drift due to the fifteenth century European colonization could not be excluded as the main factor responsible. The present mtDNA study of aboriginal remains and extant samples from the six municipal districts of the island indeed demonstrates that the pre-Hispanic colonization of La Gomera by North African people involved a strong founder event, shown by the high frequency of the indigenous Canarian U6b1a lineage in the aboriginal samples (65%).

The history of the North African mitochondrial DNA haplogroup U6 gene flow into the African, Eurasian and American continents.

Background: Complete mitochondrial DNA (mtDNA) genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA. Human mitochondrial DNA haplogroup U6 has been considered as a molecular signal of a Paleolithic return to North Africa of modern humans from southwestern Asia.

Results: Using 230 complete sequences we have refined the U6 phylogeny, and improved the phylogeographic information by the analysis of 761 partial sequences.

Mitochondrial DNA and Y-chromosome structure at the Mediterranean and Atlantic façades of the Iberian Peninsula.

Objectives: The aim of this study is to analyze mitochondrial DNA and Y-chromosome lineages in a range of Atlantic and Mediterranean populations of the Iberian Peninsula in search of genetic differences between both façades and to uncover the most probable geographic origin and coalescence ages of lineages.

Methods: The control region of mitochondrial DNA and haplogroup diagnostic positions were analyzed in 575 subjects and Y-chromosome markers were typed in 260 unrelated males. Moreover, previously published data were compiled and used in the analyses.

Introducing the Algerian mitochondrial DNA and Y-chromosome profiles into the North African landscape.

North Africa is considered a distinct geographic and ethnic entity within Africa. Although modern humans originated in this Continent, studies of mitochondrial DNA (mtDNA) and Y-chromosome genealogical markers provide evidence that the North African gene pool has been shaped by the back-migration of several Eurasian lineages in Paleolithic and Neolithic times. More recent influences from sub-Saharan Africa and Mediterranean Europe are also evident.

Distinguishing the co-ancestries of haplogroup G Y-chromosomes in the populations of Europe and the Caucasus.

Haplogroup G, together with J2 clades, has been associated with the spread of agriculture, especially in the European context. However, interpretations based on simple haplogroup frequency clines do not recognize underlying patterns of genetic diversification. Although progress has been recently made in resolving the haplogroup G phylogeny, a comprehensive survey of the geographic distribution patterns of the significant sub-clades of this haplogroup has not been conducted yet.

Ancient DNA from hunter-gatherer and farmer groups from Northern Spain supports a random dispersion model for the Neolithic expansion into Europe.

Background/principal Findings: The phenomenon of Neolithisation refers to the transition of prehistoric populations from a hunter-gatherer to an agro-pastoralist lifestyle. Traditionally, the spread of an agro-pastoralist economy into Europe has been framed within a dichotomy based either on an acculturation phenomenon or on a demic diffusion. However, the nature and speed of this transition is a matter of continuing scientific debate in archaeology, anthropology, and human population genetics.

Genetics, environment, and diabetes-related end-stage renal disease in the Canary Islands.

Aims: Type 1 and type 2 diabetes, complicated with renal disease, have a significantly higher incidence in the Canary Islands than in mainland Spain and other European countries. Present-day Canarian inhabitants consist of a mixed population with North African indigenous and European colonizer ancestors who have rapidly evolved from a rural to an urban life style. The aim of this work was to assess the possible role of genetic and environmental factors on diabetes-related end-stage renal disease incidence in the Canary Islands.

New insights into the Tyrolean Iceman's origin and phenotype as inferred by whole-genome sequencing.

The Tyrolean Iceman, a 5,300-year-old Copper age individual, was discovered in 1991 on the Tisenjoch Pass in the Italian part of the Ötztal Alps. Here we report the complete genome sequence of the Iceman and show 100% concordance between the previously reported mitochondrial genome sequence and the consensus sequence generated from our genomic data. We present indications for recent common ancestry between the Iceman and present-day inhabitants of the Tyrrhenian Sea, that the Iceman probably had brown eyes, belonged to blood group O and was lactose intolerant.

Susceptibility to primary angle closure glaucoma in Saudi Arabia: the possible role of mitochondrial DNA ancestry informative haplogroups.

Purpose: In a previous preliminary analysis we reported that mitochondrial DNA (mtDNA) haplogroup R0a was significantly more frequent in primary angle closure glaucoma (PACG) Saudi patients than in healthy Saudi controls. This result prompted us to extend our work using a significant larger Saudi PACG cohort and more healthy controls.

Methods: We sequenced the mtDNA regulatory hypervariable region-I (HVS-I) and coding regions, comprising haplogroup diagnostic polymorphisms, in 227 PACG Saudi patients and compared their haplogroup frequencies with those obtained from 186 matched healthy controls (free of PACG by examination) and from a large sample of 810 healthy Saudi Arabs representing the general Saudi population.

Mitochondrial DNA and Y-chromosome microstructure in Tunisia.

Mitochondrial DNA (mtDNA) and Y-chromosome variation has been studied in Bou Omrane and Bou Saâd, two Tunisian Berber populations. In spite of their close geographic proximity, genetic distances between them were high and significant with both uniparental markers. A global analysis, including all previously studied Tunisian samples, confirmed the existence of a high female and male population structure in this country.

Mitochondrial DNA lineages of African origin confer susceptibility to primary open-angle glaucoma in Saudi patients.

Purpose: We previously reported that certain mitochondrial DNA (mtDNA) polymorphisms in the coding region may be involved in the pathogenesis for primary open-angle-glaucoma (POAG). This encouraged us to extend our work and assess whether mtDNA diagnostic polymorphisms, defining geographically structured haplogroups, could be associated with the development of POAG.

Methods: We sequenced the mtDNA regulatory hypervariable region-I (HVS-I) region and coding regions, comprising haplogroup diagnostic polymorphisms, in 176 POAG patients and 186 matched healthy controls (free of glaucoma by examination) of Saudi Arabia ascendancy.

Eurasian and Sub-Saharan African mitochondrial DNA haplogroup influences pseudoexfoliation glaucoma development in Saudi patients.

Purpose: To investigate whether different mitochondrial DNA (mtDNA) haplogroups have a role on the development of pseudoexfoliation glaucoma (PEG) in the Saudi Arab population.

Methods: The mtDNA regulatory region and coding regions comprising mtDNA haplogroup diagnostic polymorphisms were sequenced in patients with PEG (n=94), healthy matched controls (free of PEG; n=112) and a healthy Saudi Arab population group (n=810).

Results: The Eurasian haplogroup T and the Sub-Saharan African Haplogroup L2 confer susceptibility to PEG, whereas the Eurasian haplogroup N1 was associated with reduced risk to develop PEG in the Saudi Arab population.

A major Y-chromosome haplogroup R1b Holocene era founder effect in Central and Western Europe.

The phylogenetic relationships of numerous branches within the core Y-chromosome haplogroup R-M207 support a West Asian origin of haplogroup R1b, its initial differentiation there followed by a rapid spread of one of its sub-clades carrying the M269 mutation to Europe. Here, we present phylogeographically resolved data for 2043 M269-derived Y-chromosomes from 118 West Asian and European populations assessed for the M412 SNP that largely separates the majority of Central and West European R1b lineages from those observed in Eastern Europe, the Circum-Uralic region, the Near East, the Caucasus and Pakistan. Within the M412 dichotomy, the major S116 sub-clade shows a frequency peak in the upper Danube basin and Paris area with declining frequency toward Italy, Iberia, Southern France and British Isles.

Improved ethanol precipitation of DNA.

In this Short Communication, a shorter version of the standard DNA ethanol precipitation and purification protocol is described. It uses a mixture of 70% ethanol, 75 mM ammonium acetate and different concentrations of different carriers to perform DNA precipitation and washing in only one step.

The mitochondrial DNA variant 16189T>C is associated with coronary artery disease and myocardial infarction in Saudi Arabs.

By virtue of the functional role of the mitochondrion in energy and reactive oxygen species production, mutations in mitochondrial DNA (mtDNA) are potential candidates for cardiovascular-related disorders. Further, the mtDNA is extremely polymorphic and several diagnostic single-nucleotide polymorphisms have been used to assort sequences into haplogroups with defined continental and regional ranges. However, the relevance of these haplogroups and mutations with respect to coronary artery disease (CAD) susceptibility remains unclear.

Saudi Arabian Y-Chromosome diversity and its relationship with nearby regions.

Background: Human origins and migration models proposing the Horn of Africa as a prehistoric exit route to Asia have stimulated molecular genetic studies in the region using uniparental loci. However, from a Y-chromosome perspective, Saudi Arabia, the largest country of the region, has not yet been surveyed. To address this gap, a sample of 157 Saudi males was analyzed at high resolution using 67 Y-chromosome binary markers.