|
Post by djoser-xyyman on Dec 21, 2019 8:10:36 GMT -5
Human genomic diversity where the Mediterranean joins the Atlantic Candela L Hernández, Guillermo Pita, Bruno Cavadas, Saioa López, Luis J Sánchez-Martínez, Jean-Michel Dugoujon, Andrea Novelletto, Pedro Cuesta, Luisa Pereira, Rosario Calderón
Abstract Throughout the past few years, a lively debate emerged about the timing and magnitude of the human migrations between the Iberian Peninsula and the Maghreb. Several pieces of evidence, including archaeological, anthropological, historical and genetic data, have pointed to a complex and intermingled evolutionary history in the western Mediterranean area. To study to what extent connections across the Strait of Gibraltar and surrounding areas have shaped the present-day genomic diversity of its populations, we have performed a screening of 2.5 million single nucleotide polymorphisms (SNPs) in 142 samples from southern Spain, southern Portugal and Morocco. We built comprehensive datasets of the studied area and we implemented multistep bioinformatic approaches to assess population structure, demographic histories and admixture dynamics. Both local and global ancestry inference showed an internal substructure in the Iberian Peninsula, mainly linked to a differential African ancestry. Western Iberia, from southern Portugal to Galicia, constituted an independent cluster within Iberia characterized by an enriched African genomic input. Migration time modelling showed recent historic dates for the admixture events occurring both in Iberia and in the North of Africa. However, an integrative vision of both paleogenomic and modern DNA data allowed us to detect chronological transitions and population turnovers that could be the result of trans-continental migrations dating back from Neolithic times. The present contribution aimed to fill the gaps in the modern human genomic record of a key geographic area, where the Mediterranean and the Atlantic come together.
|
|
|
Post by djoser-xyyman on Dec 21, 2019 8:23:02 GMT -5
The data has consistently shown there is a strong connection between western African and the western Atlantic of Europe.
|
|
|
Post by djoser-xyyman on Dec 21, 2019 10:24:27 GMT -5
Guess I am not the only one
"The proximity between Iberia and the Maghreb not only includes the vicinity of the Strait of Gibraltar (14.4 km, its narrowest width), which has crossing difficulties due to the strong winds and dangerous currents, but also the Alboran Sea (~380 km in length and a maximum width of 180 km) to the east. It contains the small island of Alboran, as an intermediate stopover, in the distance separating Spain and Morocco, which high mountains allow the sight of land during the crossing. All these characteristics have made the western Mediterranean area most suitable for maritime contacts involving the southern and northern shores. The conjunction of archeological, anthropological, historical and genetic data confirms the rich scenarios of ancient human movements in the region.
Migration events in the west Mediterranean were especially abundant over the Neolithic and Bronze Ages (Veeramah 2018). Then, the process continued in later prehistoric times followed by a sustained continuity during the ancient history onwards. This likely picture has justified the substantial role of the Strait of Gibraltar and the Alboran Sea as the main maritime routes connecting Africa and Europe in its westernmost side. "
|
|
|
Post by djoser-xyyman on Dec 21, 2019 10:34:39 GMT -5
Population genomic analysis of elongated skulls reveals extensive female-biased immigration in Early Medieval Bavaria. Veeramah KR
|
|
|
Post by djoser-xyyman on Dec 21, 2019 10:42:14 GMT -5
"Northern Africa has had a complex prehistory and history. Recently, new discoveries and dating of artifacts and fossils at the Jebel Irhoud Middle Stone site near Casablanca (Morocco) have reported the oldest remains of a H. sapiens lineage in North Africa (~310,000 ya) (Hublin et al. 2017; Richter et al. 2017). The presence of successive prehistoric industries in northern Africa associated with H. sapiens (Aterian, Iberomaurusian and Capsian) has raised questions on population continuity or discontinuity (Irish 2000; Barton et al. 2013). In the Maghreb, the Iberomaurusian industry (18,000 to 9500 BC) was similar to that found in Mediterranean Iberian Peninsula sites with Upper Magdalenian (13,500-11,800 BP) and Epimagdalenian (11,800- 10,000 BP) chronologies. During Upper Magdalenian and until 12,800 BP, harpoons became common along Mediterranean Levantine Spanish coasts (Villaverde et al. 2012). A harpoon was found in Taforalt cave (northeastern Moroccan Rif) (Camps 1974). Evidence of big-game fishing (including harpoons) recovered from the Andalusian Nerja cave (Malaga, Spain) during the Upper Magdalenian would again support signatures of contacts between the north and southwestern Mediterranean coasts. Southern Iberia and the Maghreb share similar characteristics with respect to the Neolithization process, a finding that has been interpreted as the consequence of strategic relationships across the western Mediterranean area (Manen et al. 2007; Linstädter et al. 2012; Isern et al. 2014; Carrasco et al. 2016; Martínez-Sánchez et al. 2018). The introduction of the Neolithic in the Iberian Peninsula (also in the Maghreb) was earlier than in other parts of Europe situated more to the east, with a rapid colonization of Iberia by Neolithic migrants (González- Fortes et al. 2019). Maritime routes were presumably the main vectors of those movements. In this respect, Cruz Berrocal (2012) and Cortés Sánchez et al. (2012) provided dates on when the Neolithic transition took place in Iberia (∼7650–7550 years BP) as well as sources of those migrants. Recently, Martins et al. (2015), using 14C dating procedures on different samples, placed the appearance of the “Neolithic package” in Iberia ca 5500 cal. BC."
|
|
|
Post by djoser-xyyman on Dec 21, 2019 10:48:08 GMT -5
"A particular and integrative human vision of this geographic region comprising samples from the southern Iberian Peninsula (from both Portugal and Spain) and northwestern Africa has not been explored. Therefore, in the present study, we performed a GW screening of living western Mediterranean autochthonous people from southern Portugal, southern Spain (western and eastern Andalusia) and Morocco (i.e., Berbers). Fine details on population structure, demographic histories and admixture dynamics of this metapopulation are provided here. Comparisons with dense SNP data based on modern and ancient DNA in other European, North African and Near Eastern populations shed new insights into the timing and extent of human migrations between continents and the gene flow connecting populations. As expected, the impact of the sub-Saharan ancestral gene pool on Moroccan Berber genomes is by far stronger than that found in southern Iberians, 13.80±3.41% vs 1.41±0.72%, respectively. Figuig Berbers showed the highest proportion (14.02±1.27%), although differences among Berber Downloaded from academic.oup.com/mbe/advance-article-abstract/doi/10.1093/molbev/msz288/5670533 by guest on 11 December 2019 5 populations were not significant. Coudray et al. (2009) and Hernández et al. (2015) showed an increased representation of sub-Saharan mtDNA haplogroups in Figuig Berbers (i.e., high prevalence of L-derived lineages)."
|
|
|
Post by djoser-xyyman on Dec 21, 2019 10:55:24 GMT -5
"Moving forward into a European-Mediterranean landscape (Figure 2A), the PCA in Figure 2B illustrates the structure of human populations settled along the N-S and E-W axes of the continents. The first principal component (PC1) absorbed a major variance (76.4%) and separated sub-Saharan individuals (indicated in different shades of purple) from European, Near Easterner and North African people. Concordant with PC2 (6.9%), European samples confined in the upper left quadrant II of the plot are distributed along a latitudinal axis, with Finns at the top and Iberians plus Italians at the bottom. The N-S directionality in the genetic patterns of variation resembles the close correlation between genetic and geographic positions of populations observed elsewhere (e.g., the case of Europe, Novembre and Ramachandran 2011). Southwestern Iberian individuals (present study) appear slightly displaced from the core of the Iberian samples (excepting some Spanish Basques) toward the positive values of PC1 (quadrant IV). North African clusters are farther from one another than Europeans, whereas Near-Easterners (in green) are positioned between Europeans and North Africans. The PCA also revealed an apparent absence of a longitudinal population structure along the North African fringe. Convergent on SNP data, some North African samples display an interesting proximity to sub-Saharan people, indicating scenarios of differential admixture"
|
|
|
Post by djoser-xyyman on Dec 21, 2019 11:19:48 GMT -5
This means no migration fom the Near East. Also there was never ever migration of Neolithic from the Near east. Means also that the Sahara was the source as I have been saying for years.
"The PCA also revealed an apparent absence of a longitudinal population structure along the North African fringe. Convergent on SNP data, some North African samples display an interesting proximity to sub-Saharan people, indicating scenarios of differential admixture.
The observed pattern seems to disagree with conclusions from Arauna et al. (2017), who stated that all of northern Africa is mixed with the Near East.
We found a positive and significant correlation between latitude and the two European inferred ancestral clusters
According to our GW data, Iberians, including southern autochthonous people, are mainly mixing outcomes of ancient settlers in the Peninsula, represented by the Basques and northwestern Europeans, with a reduced contribution of Maghreb and Near East as well as a minor component of sub-Saharan people. The latter influence seems to be old because of the few and short DNA tracts observed on Iberian chromosomes.
The properties of recombination result in the inability of dense SNP screenings for properly date deep migration episodes, reaching an upper limit of around 4,500 BP (~160 generations), after which recombination removes reliable detectable haplotypes (Hellenthal et al. 2014). The stochastic process of recombination is extremely complicated, with some pieces of the “ancestral recombination graph” showing their MRCA long before others (Nordborg 2003). Consequently, estimations of admixture dates are considerably young and uncertain.
An example can be found in the relatively high African genetic signatures in Iberia, especially along its western side. These signals have been mainly detected through haploid, uniparental markers. Modern mtDNA studies have revealed that a certain proportion of African lineages were introduced in the Iberian Peninsula around Early Holocenic times (Cerezo et al. 2012; Hernández et al. 2015). Reciprocally
Recently, González-Fortes et al. (2019) reported a mitogenome of clear sub-Saharan origin (L2a1) in a 3600-year-old sample from an Andalusian cave (Córdoba), suggesting trans- continental migrations predating the Bronze Age. Additionally, in Camino de las Yeseras, an especially interesting Late Chalcolithic central Iberian site, a female individual was recovered and genetically distinguished by harboring the L1b mtDNA lineage (Szécsényi-Nagy et al. 2017). Both maternal haplogroups are frequently found in western Africa (see Hernández et al. 2015 and datasets S3-S4 therein). Olalde et al. (2019) reported a North African ancestry for both mtDNA (M1a1b1) and Y-chromosome (E1b1b1a) lineages in a male individual from Camino de las Yeseras."
|
|
|
Post by djoser-xyyman on Dec 21, 2019 11:49:55 GMT -5
Keep in mind these are labeled "European". This means again. No migration of Neolithics from the Near East
"The European component present in Berbers, at least those settled in northwestern Africa (present study), is generally higher than that observed from the Near East, signifying more intense contacts with the west than eastern Mediterranean. A portion of that European component comes from the Basque genome, indicating old relationships with Iberia"
They play there games with the genetic markers chosen for the study. Read on....
"Some genetic diversity studies have observed closer relationships between North Africans and Europeans than the former with sub-Saharans (Ennafaa et al. 2009; Fadhlaoui-Zid et al. 2013). However, interesting and different scenarios have been found that depend on the nature of genetic markers of study. For instance, the European ancestry inferred for North African individuals appears less represented when using GW data than when using haploid markers. This is especially evident for mtDNA, where the European contribution can exceed 50% (Coudray et al. 2009; Font- Porterias et al. 2018). Instead, genomic analyses performed here showed an average European ancestral proportion in northern Africa of 12.2±7.1% (see Table S2 and Figure S1).
Nevertheless, and as expected, the major proportion of North African genomic diversity, such as ADMIXTURE data states, would be due to the ‘native’ Maghrebi cluster (62.5±20.5%), which is far more frequent in the west than in its eastern side (see Figure 2C). In fact, the weight of the Maghrebi component is relatively low in Libya and Egypt, where high rates of Near East ancestry are observed.
This idea has been challenged very recently, suggesting that 40% of the Iberian’s ancestry was replaced by Steppe people by 2000 BCE (Olalde et al. 2019). In the present study, we observed a switch of 30% of the Iberian ancestry from sub-Saharan into another component, called ‘Mediterranean’ for its population distribution, after BA (see Figure 5C). This fact could chronologically match the impact of BA migrations. However, it would be puzzling to associate the ‘Mediterranean’ contributor to the Steppe input, since modern Moroccan samples are mostly characterized by this ancestral source
"
|
|
|
Post by djoser-xyyman on Dec 21, 2019 12:05:19 GMT -5
"Our genomic data reflect that this road, that enabled military and commercial activities, could have acted as a vehicle for the spread of (African) genes, and that have significantly defined the contemporary internal structure within the Iberian Peninsula (see Fortes-Lima et al. 2014; Hernández et al. 2014).
Therefore, we must open the time boundaries for south to north (and reciprocally) population movements between Iberia and the Maghreb far deeper than the medieval Muslim conquest and the Roman period
"
|
|
|
Post by djoser-xyyman on Dec 21, 2019 12:06:11 GMT -5
I did not write the study ...honest
I am only the messenger. He He! He!
|
|
|
Post by kel on Dec 21, 2019 17:31:56 GMT -5
|
|
|
Post by djoser-xyyman on Dec 27, 2019 6:53:05 GMT -5
"RFMix highlighted southern Portugal as the main Iberian target for African (using Yoruban, YRI, as the African proxy) gene input (mean value= 2.09±0.71%) followed by southwestern Andalusians (Huelva) (1.21±0.53%), while this influence was comparatively weaker (0.94±0.28%) in Granada Andalusians. The presence and extent of African signatures in western Andalusia is in accordance with other previous data drawn from the analysis of mtDNA markers based on the same sample set (Hernández et al. 2015)."
"The mean number of DNA segments related to sub-Saharan ancestry per sample in southern Iberians is 75.76 with an average size of 2.54±3.14 cM. In Moroccan Berbers, the mean number of segments is 296.97, being the average size 3.26±3.66 cM."
As I mentioned. SOUTH to NORTH. Africa to Europe..... two entry POINTS Iberia and Italy(Sardinia)
"The first principal component (PC1) absorbed a major variance (76.4%) and separated sub-Saharan individuals (indicated in different shades of purple) from European, Near Easterner and North African people. Concordant with PC2 (6.9%), European samples confined in the upper left quadrant II of the plot are distributed along a latitudinal axis, with Finns at the top and Iberians plus Italians at the bottom. The N-S directionality in the genetic patterns of variation resembles the close correlation between genetic and geographic positions of populations observed elsewhere (e.g., the case of Europe, Novembre and Ramachandran 2011). Southwestern Iberian individuals (present study) appear slightly displaced from the core of the Iberian samples (excepting some Spanish Basques) toward the positive values of PC1 (quadrant IV)."
|
|
|
Post by djoser-xyyman on Dec 27, 2019 7:08:09 GMT -5
What does it mean? Yes, the migration was South to North. NOT the other way around
"North African clusters are farther from one another than Europeans, whereas Near-Easterners (in green) are positioned between Europeans and North Africans."
|
|
|
Post by djoser-xyyman on Dec 28, 2019 4:18:21 GMT -5
I can't make this stuff up.
Quote "For Moroccan aDNA samples, a chronological cline is evident, but for the Iberian samples, it would be more challenging to detect this tendency. Both groups of ancient samples deviate slightly from the corresponding present ones toward the sub-Saharan cluster. The ADMIXTURE results can shed some light on the temporal variations of different sources of ancestry in western Mediterranean over time. In Figure 5C, we can see that the percentage of the blue European component is similar in ancient and present-day European samples (0.67-0.72), while this component, high in ancient Moroccan samples (0.39-0.59), is reduced sharply in present-day samples (0.08). The ochre component (‘Mediterranean’ that could represent a Maghrebi/Near Eastern ancestry) changes from (0.05-0.22) in ancient Moroccan samples to 0.73 in contemporaneous ones, while the corresponding change in Iberians goes from zero to (0.28-0.32). The purple sub-Saharan component moves from (0.36-0.43) to 0.19 in Moroccans and from (0.29-0.32) to (0.01-0.02) in Iberians. In short, the pass in the region from ancient to present-day populations consists for Iberia in the substitution of the sub-Saharan component by that ‘Mediterranean’ cluster, while in Moroccans its considerable rise is compensated with notable reductions of European and sub- Saharan ones. These results suggest that the Maghreb component was mostly transferred to Iberia after the Neolithic, obscuring previous genetic relationships between Iberia and North Africa."
|
|