Y-chromosome analysis in Egypt suggests a genetic regional continuity in Northeastern Africa

The geographic location of Egypt, at the interface between North Africa, the Middle East, and southern Europe, prompted us to investigate the genetic diversity of this population and its relationship with neighboring populations. To assess the extent to which the modern Egyptian population reflects this intermediate geographic position, ten Unique Event Polymorphisms (UEPs), mapping to the nonrecombining portion of the Y chromosome, have been typed in 164 Y chromosomes from three North African populations. The analysis of these binary markers, which define 11 Y-chromosome lineages, were used to determine the haplogroup frequencies in Egyptians, Moroccan Arabs, and Moroccan Berbers and thereby define the Y-chromosome background in these regions. Pairwise comparisons with a set of 15 different populations from neighboring European, North African, and Middle Eastern populations and geographic analysis showed the absence of any significant genetic barrier in the eastern part of the Mediterranean area, suggesting that genetic variation and gene flow in this area follow the "isolation-by-distance" model. These results are in sharp contrast with the observation of a strong north-south genetic barrier in the western Mediterranean basin, defined by the Gibraltar Strait. Thus, the Y-chromosome gene pool in the modern Egyptian population reflects a mixture of European, Middle Eastern, and African characteristics, highlighting the importance of ancient and recent migration waves, followed by gene flow, in the region.     

Insights into Iberian population origins through the construction of highly informative Y-chromosome haplotypes using biallelic markers,STRs, and the MSY1 minisatellite

To investigate the diversity of Y chromosomes in the Iberian Peninsula and the North African population of Maghreb, we constructed superhaplotypes on the basis of 10 biallelic markers, 7 microsatellites, and 1 minisatellite located in the nonrecombining portion of the human Y chromosome. The analysis of extremely high MSY1 variability was performed by reducing the MVR-codes to modular structures. Y-STRs and MSY1 data provide information about the relationship between closely related populations such as those of Iberia. Analysis of biallelic markers allowed us to identify 7 of 12 haplogroups defined by those polymorphisms. The haplogroup background showed clear differences between Iberian populations and the North African one. The use of differently mutating Y-chromosome markers allowed us to infer different population events at different time scales: the Paleolithic background of the Iberian Peninsula, the Neolithic fingerprint on Y-chromosome lineages, and the Iron Age influence in the populations of Iberia. Implications of our results for the highly debated origin of Basques are also discussed.     

Balinese Y-chromosome perspective on the peopling of Indonesia: genetic contributions from pre-neolithic hunter-gatherers, Austronesian farmers, and Indian traders

The island of Bali lies near the center of the southern chain of islands in the Indonesian archipelago, which served as a stepping-stone for early migrations of hunter-gatherers to Melanesia and Australia and for more recent migrations of Austronesian farmers from mainland Southeast Asia to the Pacific. Bali is the only Indonesian island with a population that currently practices the Hindu religion and preserves various other Indian cultural, linguistic, and artistic traditions (Lansing 1983). Here, we examine genetic variation on the Y chromosomes of 551 Balinese men to investigate the relative contributions of Austronesian farmers and pre-Neolithic hunter-gatherers to the contemporary Balinese paternal gene pool and to test the hypothesis of recent paternal gene flow from the Indian subcontinent. Seventy-one Y-chromosome binary polymorphisms (single nucleotide polymorphisms, SNPs) and 10 Y-chromosome-linked short tandem repeats (STRs) were genotyped on a sample of 1,989 Y chromosomes from 20 populations representing Indonesia (including Bali), southern China, Southeast Asia, South Asia, the Near East, and Oceania. SNP genotyping revealed 22 Balinese lineages, 3 of which (O-M95, O-M119, and O-M122) account for nearly 83.7% of Balinese Y chromosomes. Phylogeographic analyses suggest that all three major Y-chromosome haplogroups migrated to Bali with the arrival of Austronesian speakers; however, STR diversity patterns associated with these haplogroups are complex and may be explained by multiple waves of Austronesian expansion to Indonesia by different routes. Approximately 2.2% of contemporary Balinese Y chromosomes (i.e., K-M9*, K-M230, and M lineages) may represent the pre-Neolithic component of the Indonesian paternal gene pool. In contrast, eight other haplogroups (e.g., within H, J, L, and R), making up approximately 12% of the Balinese paternal gene pool, appear to have migrated to Bali from India. These results indicate that the Austronesian expansion had a profound effect on the composition of the Balinese paternal gene pool and that cultural transmission from India to Bali was accompanied by substantial levels of gene flow.     

Alu insertion polymorphisms in NW Africa and the Iberian Peninsula: evidence for a strong genetic boundary through the Gibraltar Straits

An analysis of 11 I Alu insertion polymorphisms (ACE, TPA25, PV92, APO, FXIIIB, D1, A25, B65, HS2.43, HS3.23, and HS4.65) has been performed in several NW African (Northern, Western, and Southeastern Moroccans, Saharawi; Algerians; Tunisians) and Iberian (Basques, Catalans, and Andalusians) populations. Genetic distances and principal component analyses show a clear differentiation of NW African and Iberian groups of samples, suggesting a strong genetic barrier matching the geographical Mediterranean Sea barrier. The restriction to gene flow may be attributed to the navigational hazards across the Straits, but cultural factors must also have played a role. Some degree of gene flow from sub-Saharan Africa can be detected in the southern part of North Africa and in Saharawi and Southeastern Moroccans, as a result of a continuous gene flow across the Sahara desert that has created a south-north cline of sub-Saharan Africa influence in North Africa. Iberian samples show a substantial degree of homogeneity and fall within the cluster of European-based genetic diversity.     

Strait of Gibraltar: an effective gene-flow barrier for wind-pollinated Carex helodes (Cyperaceae) as revealed by DNA sequences, AFLP, and cytogenetic variation

The Strait of Gibraltar is the most important barrier disconnecting the landmasses of Europe and Africa on the western Mediterranean extreme. Carex helodes is a wind-pollinated species endemic to the western Mediterranean. Because molecular and cytogenetic data allow the inference of its evolutionary history, we analyzed variations in chromosome number, including meiotic chromosome behavior, amplified fragment length polymorphism (AFLP) fingerprints, and nucleotide substitutions in plastid and nuclear DNA sequences. Cytogeographic results showed that the African populations have stabilized at a single chromosome number of 2n = 74, whereas the most frequent cytotype in Iberia is 2n = 72. Phylogenetic reconstructions of 17 sequences from nine closely related species revealed that C. helodes is monophyletic and that the Moroccan populations are embedded in the Iberian lineages. The haplotype network is also consistent with a European origin of the northern African haplotype. AFLP analysis also revealed hierarchical levels of genetic variation compatible with a founder effect process responsible for the African populations. All sources of evidence support the hypothesis that the Strait of Gibraltar has been an effective gene-flow barrier, generating two isolated evolutionary lineages after their dispersal. Recent connections between the two lineages appear unlikely, whereas active gene flow occurs among populations within the two lineages.     

Migration and winter distribution of Iberian and central European black storks Ciconia nigra moving to Africa across the Strait of Gibraltar: a comparative study

This paper compares the migratory movements of Iberian and central European satellite‐tagged black storks Ciconia nigra moving to Africa across the Strait of Gibraltar. Results show that the populations differ in departure dates from breeding areas (central European birds start to move 15 d before Iberian birds), cross the Strait of Gibraltar together and reach the Sahel on similar dates. This synchronic arrival to the Sahel may be related with the onset of suitable conditions for the species after summer rains, when many pools are available for fishing. In this area, Iberian birds occupied westernmost localities compared to central European birds crossing the Strait of Gibraltar, which were distributed closer to those storks arriving in Africa across the Bosporus. This suggests that the parallel distribution of breeding and wintering areas results from posterior rearrangements of the two populations crossing Gibraltar. These patterns appear to be linked to the increasing population of central European black storks located on the western side of the migratory divide that moves throughout the western flyway to sectors of the Sahel close to their ancestral wintering grounds.     

The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data

We report a comparison of worldwide genetic variation among 255 individuals by using autosomal, mitochondrial, and Y-chromosome polymorphisms. Variation is assessed by use of 30 autosomal restriction-site polymorphisms (RSPs), 60 autosomal short-tandem-repeat polymorphisms (STRPs), 13 Alu-insertion polymorphisms and one LINE-1 element, 611 bp of mitochondrial control-region sequence, and 10 Y-chromosome polymorphisms. Analysis of these data reveals substantial congruity among this diverse array of genetic systems. With the exception of the autosomal RSPs, in which an ascertainment bias exists, all systems show greater gene diversity in Africans than in either Europeans or Asians. Africans also have the largest total number of alleles, as well as the largest number of unique alleles, for most systems. GST values are 11%-18% for the autosomal systems and are two to three times higher for the mtDNA sequence and Y-chromosome RSPs. This difference is expected because of the lower effective population size of mtDNA and Y chromosomes. A lower value is seen for Y-chromosome STRs, reflecting a relative lack of continental population structure, as a result of rapid mutation and genetic drift. Africa has higher GST values than does either Europe or Asia for all systems except the Y-chromosome STRs and Alus. All systems except the Y-chromosome STRs show less variation between populations within continents than between continents. These results are reassuring in their consistency and offer broad support for an African origin of modern human populations.     

Phylogeographic patterns of two tiger beetle species at both sides of the strait of Gibraltar (Coleoptera: Cicindelini)

The Strait of Gibraltar is one of the major barriers to gene flow between land masses of Europe and Africa at the western end of the Mediterranean. Since the opening of the Strait at the end of the Miocene 5.33 million years ago (Mya) it has exerted a strong influence on the dispersal and colonization of whole biotas, particularly with regard to the retreat of organisms during glaciation peaks and the northward colonization events during the warm periods of Pleistocene. The aim of this study is to elucidate the influence of the Strait of Gibraltar in the gene flow among populations of two tiger beetle species collected in Morocco, Cicindela campestris (L. 1758) and Lophyra flexuosa (Fabricius 1787), with regard to both new and published data from populations of southern Iberia. The phylogeographic analysis showed that Moroccan haplotypes of L. flexuosa belonged to a single coastal mitochondrial clade and that populations at both sides of` the Strait of Gibraltar were genetically well connected. The haplotype network of C. campestris showed that Moroccan populations made up a robust cluster clearly differentiated from those of Iberian and other European populations. These differences are thought to reflect the distinct evolutionary history (dispersal capacity, ecological strategies) of both species, as L. flexuosa shows an almost continuous distribution on the coasts located at both sides of the West Mediterranean, whereas C. campestris shows a patchy distribution and prefers montane habitats in the Western Palaearctic.     

Complex biogeographical distribution of genetic variation within Podarcis wall lizards across the Strait of Gibraltar

Abstract Aim To examine the effect of a known geological barrier on genetic variation within a wall lizard species complex. Location The Iberian Peninsula and North Africa. Methods Sequencing of partial 12S rRNA and cytochrome b mtDNA. Results The current distribution of genetic variability is not related to the opening of the Strait of Gibraltar. Conclusions Podarcis hispanica in North Africa is probably a species complex. The Strait of Gibraltar should not be used as a known barrier to gene flow in other land based organisms without careful sampling to test for multiple crossings since its formation.     

Spatial and temporal distribution of the neutral polymorphisms in the last ZFX intron: analysis of the haplotype structure and genealogy.

With 10 segregating sites (simple nucleotide polymorphisms) in the last intron (1089 bp) of the ZFX gene we have observed 11 haplotypes in 336 chromosomes representing a worldwide array of 15 human populations. Two haplotypes representing 77% of all chromosomes were distributed almost evenly among four continents. Five of the remaining haplotypes were detected in Africa and 4 others were restricted to Eurasia and the Americas. Using the information about the ancestral state of the segregating positions (inferred from human-great ape comparisons), we applied coalescent analysis to estimate the age of the polymorphisms and the resulting haplotypes. The oldest haplotype, with the ancestral alleles at all the sites, was observed at low frequency only in two groups of African origin. Its estimated age of 740 to 1100 kyr corresponded to the time to the most recent common ancestor. The two most frequent worldwide distributed haplotypes were estimated at 550 to 840 and 260 to 400 kyr, respectively, while the age of the continentally restricted polymorphisms was 120 to 180 kyr and smaller. Comparison of spatial and temporal distribution of the ZFX haplotypes suggests that modern humans diverged from the common ancestral stock in the Middle Paleolithic era. Subsequent range expansion prevented substantial gene flow among continents, separating African groups from populations that colonized Eurasia and the New World.     

Population structure of Cicada barbara Stål (Hemiptera, Cicadoidea) from the Iberian Peninsula and Morocco based on mitochondrial DNA analysis

We assess the genetic history and population structure of Cicada barbara in Morocco and the Iberian Peninsula, based on analysis of the mitochondrial cytochrome b gene. The divergence between Morocco and the Iberian Peninsula populations was strongly corroborated by the molecular data, suggesting genetically isolated populations with a low level of gene flow. The Ceuta population from Spanish North Africa was more similar to the Iberian populations than the surrounding Moroccan populations, suggesting that the Strait of Gibraltar has not been acting as a strict barrier to dispersal while the Rif Mountains have. The Iberian Peninsula specimens showed a signature of demographic expansion before that which occurred in Morocco, but some of the assumptions related to the demographic parameters should be considered with caution due to the small genetic variation found. The high haplotype diversity found in Morocco implies higher demographic stability than in the Iberian Peninsula populations. These results do not, however, suggest a Moroccan origin for Iberian cicadas; but the most northwest region in Africa, such as Ceuta, might have acted as a southern refuge for Iberian cicadas during the most severe climatic conditions, from where they could expand north when climate improved. The separation of two subspecies within C. barbara (C. barbara lusitanica and C. barbara barbara) finds support with these results.     

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. The presence of East-West and North-South haplogroup frequency gradients strongly reinforces the genetic complexity of this region. However, this genetic scenario is beset with a notable gap, which is the lack of consistent information for Algeria, the largest country in the Maghreb. To fill this gap, we analyzed a sample of 240 unrelated subjects from a northwest Algeria cosmopolitan population using mtDNA sequences and Y-chromosome biallelic polymorphisms, focusing on the fine dissection of haplogroups E and R, which are the most prevalent in North Africa and Europe respectively. The Eurasian component in Algeria reached 80% for mtDNA and 90% for Y-chromosome. However, within them, the North African genetic component for mtDNA (U6 and M1; 20%) is significantly smaller than the paternal (E-M81 and E-V65; 70%). The unexpected presence of the European-derived Y-chromosome lineages R-M412, R-S116, R-U152 and R-M529 in Algeria and the rest of the Maghreb could be the counterparts of the mtDNA H1, H3 and V subgroups, pointing to direct maritime contacts between the European and North African sides of the western Mediterranean. Female influx of sub-Saharan Africans into Algeria (20%) is also significantly greater than the male (10%). In spite of these sexual asymmetries, the Algerian uniparental profiles faithfully correlate between each other and with the geography.     

Different genetic components in the Ethiopian population,identified by mtDNA and Y-chromosome polymorphisms.

Seventy-seven Ethiopians were investigated for mtDNA and Y chromosome-specific variations, in order to (1) define the different maternal and paternal components of the Ethiopian gene pool, (2) infer the origins of these maternal and paternal lineages and estimate their relative contributions, and (3) obtain information about ancient populations living in Ethiopia. The mtDNA was studied for the RFLPs relative to the six classical enzymes (HpaI, BamHI, HaeII, MspI, AvaII, and HincII) that identify the African haplogroup L and the Caucasoid haplogroups I and T. The sample was also examined at restriction sites that define the other Caucasoid haplogroups (H, U, V, W, X, J, and K) and for the simultaneous presence of the DdeI10394 and AluI10397 sites, which defines the Asian haplogroup M. Four polymorphic systems were examined on the Y chromosome: the TaqI/12f2 and the 49a,f RFLPs, the Y Alu polymorphic element (DYS287), and the sY81-A/G (DYS271) polymorphism. For comparison, the last two Y polymorphisms were also examined in 87 Senegalese previously classified for the two TaqI RFLPs. Results from these markers led to the hypothesis that the Ethiopian population (1) experienced Caucasoid gene flow mainly through males, (2) contains African components ascribable to Bantu migrations and to an in situ differentiation process from an ancestral African gene pool, and (3) exhibits some Y-chromosome affinities with the Tsumkwe San (a very ancient African group). Our finding of a high (20%) frequency of the "Asian" DdeI10394AluI10397 (++) mtDNA haplotype in Ethiopia is discussed in terms of the "out of Africa" model.     

Autosomal, mtDNA, and Y-chromosome diversity in Amerinds: pre- and post-Columbian patterns of gene flow in South America

To evaluate sex-specific differences in gene flow between Native American populations from South America and between those populations and recent immigrants to the New World, we examined the genetic diversity at uni- and biparental genetic markers of five Native American populations from Colombia and in published surveys from native South Americans. The Colombian populations were typed for five polymorphisms in mtDNA, five restriction sites in the beta-globin gene cluster, the DQA1 gene, and nine autosomal microsatellites. Elsewhere, we published results for seven Y-chromosome microsatellites in the same populations. Autosomal polymorphisms showed a mean G(ST) of 6.8%, in agreement with extensive classical marker studies of South American populations. MtDNA and Y-chromosome markers resulted in G(ST) values of 0.18 and 0.165, respectively. When only Y chromosomes of confirmed Amerind origin were used in the calculations (as defined by the presence of allele T at locus DYS199), G(ST) increased to 0.22. G(ST) values calculated from published data for other South American natives were 0.3 and 0.29 for mtDNA and Amerind Y chromosomes, respectively. The concordance of these estimates does not support an important difference in migration rates between the sexes throughout the history of South Amerinds. Admixture analysis of the Colombian populations suggests an asymmetric pattern of mating involving mostly immigrant men and native women.     

Out of Africa and back again: nested cladistic analysis of human Y chromosome variation

We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of approximately 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.      

Y chromosomes traveling south: the cohen modal haplotype and the origins of the Lemba--the "Black Jews of Southern Africa"

The Lemba are a traditionally endogamous group speaking a variety of Bantu languages who live in a number of locations in southern Africa. They claim descent from Jews who came to Africa from "Sena." "Sena" is variously identified by them as Sanaa in Yemen, Judea, Egypt, or Ethiopia. A previous study using Y-chromosome markers suggested both a Bantu and a Semitic contribution to the Lemba gene pool, a suggestion that is not inconsistent with Lemba oral tradition. To provide a more detailed picture of the Lemba paternal genetic heritage, we analyzed 399 Y chromosomes for six microsatellites and six biallelic markers in six populations (Lemba, Bantu, Yemeni-Hadramaut, Yemeni-Sena, Sephardic Jews, and Ashkenazic Jews). The high resolution afforded by the markers shows that Lemba Y chromosomes are clearly divided into Semitic and Bantu clades. Interestingly, one of the Lemba clans carries, at a very high frequency, a particular Y-chromosome type termed the "Cohen modal haplotype," which is known to be characteristic of the paternally inherited Jewish priesthood and is thought, more generally, to be a potential signature haplotype of Judaic origin. The Bantu Y-chromosome samples are predominantly (>80%) YAP+ and include a modal haplotype at high frequency. Assuming a rapid expansion of the eastern Bantu, we used variation in microsatellite alleles in YAP+ sY81-G Bantu Y chromosomes to calculate a rough date, 3,000-5,000 years before the present, for the start of their expansion.     

Combined use of biallelic and microsatellite Y-chromosome polymorphisms to infer affinities among African populations.

To define Y-chromosome haplotypes, we studied seven biallelic polymorphic sites. We combined data with those from four dinucleotide-repeat polymorphisms, to establish Y-chromosome compound superhaplotypes. Eight biallelic haplotypes that matched the dendrogram proposed by other investigators were identified in 762 Y chromosomes from 25 African populations. For each biallelic site, coalescence time of lineages carrying the derived allele was estimated and compared with previous estimates. The "ancestral" haplotype (haplotype 1A) was observed among Ethiopians, "Khoisan" (!Kung and Khwe), and populations from northern Cameroon. Microsatellite distributions within this haplotype showed that the Khoisan haplotypes 1A are widely divergent from those of the other two groups. Populations from northern Africa and northern Cameroon share a haplotype (i.e., 1C), which is not observed in other African populations but represents a major Eurasian cluster. Haplotypes 1C of northern Cameroon are clearly distinct from those of Europe, whereas haplotypes 1C of northern African are well intermingled with those of the other two groups. Apportionment of diversity for the Y-chromosomal biallelic haplotypes was calculated after populations were clustered into different configurations. Despite some correspondence between language affiliation and genetic similarity, geographic proximity seems to be a better predictor of genetic affinity.     

The genetic population structure of Buthus occitanus (Scorpiones: Buthidae) across the Strait of Gibraltar: calibrating a molecular clock using nuclear allozyme variation

I assess here the importance of the Strait of Gibraltar as a barrier to gene flow for populations of the scorpion Buthus occitanus . This polytypic buthid scorpion occurs in Europe and in North Africa where it is morphologically more diverse. The phylogenetic relationship between B. occitanus populations across the Strait of Gibraltar is investigated by nuclear allozymes analysis (15 loci scored). Phylogenetic analysis based on estimated gene frequency data results in a tree topology that divides the populations into three clades, i.e. a European, an Atlas (= Morocco samples) and a Tell-Atlas clade (= Tunisian samples). The Tell-Atlas clade grouped with the European clade with a rather high bootstrap support of 70%. Within these clades low levels of genetic variability are observed. Calibrating a molecular clock under the assumption that the European populations are autochthonous and have been isolated from the North African for at least 5.33 Myr reveals a divergence rate of 0.060 genetic distance (D) per Myr estimated between European and Moroccan samples and 0.036D Myr⁻¹ between European and Tunisian samples, respectively.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 519–534.     

The Pyrenees as a cradle of plant diversity: phylogeny,phylogeography and niche modeling of Saxifraga longifolia

The current distribution of most species results from ecological niche, past distribution, and migrations during glacial–interglacial periods and in situ evolution. Here, we disentangle the colonization history of Saxifraga longifolia Lapeyr., a limestone plant abundant in the Pyrenees and rare in other Iberian mountains and the African Atlas. Our working hypothesis is that the current distribution results from the shrinkage of a more extensive distribution in previous cold periods. We sampled 160 individuals of 32 populations across the whole distribution range and sequenced four DNA regions (rpl32-trnL, rps16-trnQ, trnS-trnG, and ITS). Ecological conditions were modeled to identify factors promoting high genetic diversity and long-term persistence areas for S. longifolia. In addition, we inferred phylogenetic relationships, phylogeographic divergence, genetic diversity, and migration routes. Seven plastid haplotypes were found, of which six occur in the Pyrenees and one in the High Atlas (Morocco). Discrete phylogeographic analysis (DPA) estimated migration routes predominantly from the Pyrenees to the other areas. Colonization events to those areas appear to have taken place recently given that the rest of the Iberian mountains do not harbor exclusive haplotypes. Iberian–Northern African distribution was inferred to be the result of long-distance dispersal because the split between Iberian and High Atlas haplotypes is estimated to have taken place in the last 4 million years ago when the Strait of Gibraltar was already open. Migrations from the Pyrenees to the south may have been favored by a corridor of predominant limestone rocks along Eastern Iberia, followed by successful overcoming the Strait of Gibraltar to reach northern Africa.     

Description of a simple multiplex PCR-SSCP method for AB0 genotyping and its application to the peopling of the Canary Islands

A simple and affordable multiplex polymerase chain reaction-single-strand conformation polymorphism method is proposed for the molecular study of AB0 polymorphisms. Application of this method to the peopling of the Canary Islands, analyzing a total of 2,200 chromosomes, detected that in addition to Berbers and Basques, the rare alleles 0210 and O303 are also present in the Iberian Peninsula and in the Canary Islands. Allele B101, with the highest frequency in Northwest (NW) Africa, shows a negative correlation (R = -0.822, p = 0.023) between geographic distances from this continent and insular frequencies, congruent with a main aborigine colonization from East to West still detectable today. Similar to previous autosomal studies, admixture estimations point to a major Iberian contribution (82 +/- 0.5%) to the Canary Islands, although, in some islands as La Gomera, the NW African component raised to 62 +/- 4.3%.