The authors
don't at all rely on the Moorjani et al or Hellenthal et al papers. They
rely on the phylogeography of the complete mitochrondrial sequences, a Founder Analysis (FA) methodology, and a Bayesian analysis. It's obvious in a close reading of the discussion and results sections as well as the methods section and the supplementary info section. That's what the paper is about.
What they do is
contrast the results of Moorjani et al and Hellenthal et al, which propose an almost entirely late date for the arrival of SSA autosomal input, with their results from uniparental marker analysis, and make a case for the fact that there is still a role of this kind of analysis, and that it may indeed be more accurate as to timing, and can serve to correct the failures of current methods of autosomal analysis with regard to problems with the dating of admixture. I happen to agree with them for what it's worth.
This is from the paragraph where they mention the Moorjani and Hellenthal papers.
"Date estimates for migrations across the Mediterranean Basin and the Sahara desert based on mtDNA data do not generally match the ones inferred by genome-wide information, these last tending to be considerably younger.
The current limitation on date estimates for admixture based on genome wide diversity, due to the phenomenon of recombination, shows the continued usefulness of uniparental markers to shed light on the human evolution history, spanning 200,000 years. In particular, our work supports the existence of an ancient, frequently denied, bridge connecting the Maghreb and Andalusia, located just across the Strait of Gibraltar but also possibly in a more eastern position with a pier on the small island of Alboran."
As for the precise causes of this "modern" admixture, this is what they have to say, and it
is broader than just the Muslim era. However, the connection to Roman domination is not explored, beyond a reference to the joint administration of Northwest Africa and Iberia during the Roman period. Rather, the focus, other than the Islamic Era migration, is on the Atlantic slave trade.
"The recent migration peaks identified in the
FA of U6 and L lineages could be associated with the Islamic rule of Iberia and the slave trade period, respectively. The HVS-I FA attributes a comparatively lower proportion of these recently introduced sequences into Iberia when compared with the post-glacial one: 1/3 vs 2/3, respectively. The analysis performed by [
26] on the
phylogeography of
L sequences observed in
Iberia and
remaining Europe pointed to
65% of its introduction in recent times (
Romanization period, Islamic expansion and Atlantic slave trade), and 35% at older times, as earlier as 11ky. The
complete sequence based FA for U6 agrees more with these results, attributing a half-half proportion of sequences in both periods, showing the higher resolution of complete mitogenomes. The
historical-based expectation of a higher proportion of newly introduced U6 lineages in Andalusia was confirmed: 70% against 30% in the earlier migration."
As to this Spanish slave trade admixture they also have this to say:
"In contrast,
only 24.2% (f1) and 20.3% (f2) of the L-lineages that entered Europe in the historic period match the ones that arrived in North Africa, suggesting mainly independent introduction routes. As our data suggest,
an entrance of these lineages into Europe directly from sub-Saharan Africa in the historic period is likely related with the slave-trade in Europe."
They seem to be proposing that while L1 is a mixed bag in terms of time of arrival, the great majority of the specific L2 and L3 clades that entered Iberia is the result of the trans-Atlantic slave trade.
"The position of the Iberian samples within
L2 and L3 phylogenies is of considerable complexity. In most cases, Iberian sequences do not cluster with the North Africans sequences but rather with those from the Middle East or Europe. Interestingly, the Spanish samples showed a tendency to group together in the trees although they originate from very distant peninsular regions.
It is likely that some of these Spanish mitochondrial sequences may correspond to descendants of emigrants to Hispanoamerica who returned to the Peninsula after mixing with Afro-American people."
Always heard the Dido story as a child. Legend (local) also has it here that she visited Malta and contemplated in building her new city here, but it was far too small for her aspirations. Maybe its not a far fetched story considering its believed that it was the Phoenicians who founded the old town of Maleth (todays Mdina) some 700BC and two temples existed already in the entrance of the two largest harbours, Astarte and Melqart. Punic tombs are found all over the Islands.
