New Study: Ancient DNA Reveals Mobility Patterns in Algarve (11th-13th Centuries)

[LusitaniAres]

Hello everyone,
I came across an interesting study published in Archaeological and Anthropological Sciences that analyzes ancient DNA to explore population mobility in the Algarve, South Portugal, during the transition from Muslim to Portuguese Christian rule (11th-13th centuries). The findings offer new insights into the demographic dynamics of this period.

Key Points:


Muslim individuals were predominantly local (~95%), with a small percentage likely originating from the Maghreb or eastern Spain.
In contrast, the Christian population showed significant mobility, with nearly 50% being non-local, especially males, with origins along the Guadiana River and northern/northeastern Iberian regions.
This suggests asymmetric migration patterns during the Reconquista, challenging assumptions of uniform population mixing.


The full study is available here: https://link.springer.com/article/10.1007/s12520-025-02322-3
I’d love to hear your thoughts! How do these findings align with or challenge existing views on medieval Iberian migrations? For those who argue Iberians have significant Moorish ancestry, does this data support or refute that idea—especially given the local nature of the Muslim population? Are there other genetic studies that could complement this to better understand the modern Iberian genetic makeup?

[Ruderico]

4 samples had already been published in another study, this one really doesn't add anything we didn't already know.

https://i.imgur.com/3DCtxAV.jpeg



The indigenous islamic population largely derived from the same population that had lived there since the Roman period.
The conquest by the Kingdom of Portugal immediately saw the arrival of non-local colonists, whereas the local population suffered the blunt of the horrors of war.
While not present in this study, we can see the modern population has a distinct genetic profile suggesting this colonisation process was on going for a while - I've lost count of the amount of Algarvians' family trees with deep roots in other areas of the country.
Modern Algarvians aren't particularly different from the rest of the country, and are still closely related to Galicians more so than to SW Spanish

https://pubmed.ncbi.nlm.nih.gov/31816048/
https://imgur.com/qipDXh2

[Sebastianus Rex]

No suprise for me, the historical evidence and previous modern genetic studies already pointed to similar conclusions. But always good to have new data, thanks for posting.

[gixajo]

Modern Algarvians aren't particularly different from the rest of the country, and are still closely related to Galicians more so than to SW Spanish
]

I haven't read the study yet, but reading this thread... How does what you're saying combine with what the OP said in their first post?:


In contrast, the Christian population showed significant mobility, with nearly 50% being non-local, especially males, with origins along the Guadiana River and northern/northeastern Iberian regions.

Edit:What OP said is actually, at least in the abstract:
Conversely, the Christian population displayed extensive mobility, greater for males than females, with nearly 50% non-local to the Algarve. Potential origins were diverse and included regions along the Guadiana River and N/NE areas.

[Ruderico]

I haven't read the study yet, but reading this thread... How does what you're saying combine with what the OP said in their first post?:



Edit:What OP said is actually, at least in the abstract:

The study doesn't analyse what happened 800 years after the event, just that these few Christian samples are non-local immediately after the conquest. The mobility was expected, and continued to exist until today, the whole country went through a process of genetic homogenisation, as always happens in populations who dwell in a relatively restricted area - in this case the country of Portugal.

This said the largest vector was a north-south movement of people, and historically NW Portugal was always by far the most densely populated part of the country, even as recently as the 1800s.

https://i.imgur.com/Kipxk2e.png

[gixajo]

The study doesn't analyse what happened 800 years after the event, just that these few Christian samples are non-local immediately after the conquest. The mobility was expected, and continued to exist until today, the whole country went through a process of genetic homogenisation, as always happens in populations who dwell in a relatively restricted area - in this case the country of Portugal.

This said the largest vector was a north-south movement of people, and historically NW Portugal was always by far the most densely populated part of the country, even as recently as the 1800s.
]

We're talking about what this study says, you're talking about other studies.


This study says in the abstract:
Conversely, the Christian population displayed extensive mobility, greater for males than females, with nearly 50% non-local to the Algarve. Potential origins were diverse and included regions along the Guadiana River and N/NE areas.


But let's see, when you read this:


Conversely, the Christian population displayed extensive mobility, greater for males than females, with nearly 50% non-local to the Algarve. Potential origins were diverse and included regions along the Guadiana River and N/NE areas.

Isn't it precisely saying , that the contributions added to the native population during the "Reconquista" are not only from solely from Galicia? Because we're talking about the 50% added in medieval times to the 50% native population, and whose origins are "N/NE Iberia" (which might not even include Galicia due to its ambiguity, since Galicia is NW, but I suppose it does include them and they are logically the majority) and "regions around the Guadiana River" which also include non-Portuguese regions, and non-Galician contributions (which surely also had mainly Galician contributions during the Reconquista).

Do you have access to the full study? What else does it specify about those contributions?

[gixajo]

I have to go now; I'm working this weekend. Genetics studies are usually fully accessible on the work computers. If I can access the complete study, I'll try to read the conclusions and clear up any doubt.

But I still understand that this study seems to say that there were more contributions to the population during the recolonization of the Portuguese reconquest apart from the well known and totally logical Galician contributions.

At least according to what the OP posted as "Key contributions".


Key Points:

Muslim individuals were predominantly local (~95%), with a small percentage likely originating from the Maghreb or eastern Spain.
In contrast, the Christian population showed significant mobility, with nearly 50% being non-local, especially males, with origins along the Guadiana River and northern/northeastern Iberian regions.
This suggests asymmetric migration patterns during the Reconquista, challenging assumptions of uniform population mixing.

And don't worry Ruderaico, I don't intend to "Spanishize" Portugal, I just want to know what the study says.

I like having another independent country with its own idiosyncrasies as a neighbor on the peninsula, and I like that that country is Portugal, and that its modern inhabitants are largely related with Galicians.:D

[LusitaniAres]

To clear up the doubts:

The study is primarily an isotope study (87Sr/86Sr, δ18O, δ34S) with updated Iberian isoscapes + machine learning for provenance assignment. They only did aDNA on a subset of the Muslim samples (to confirm genetic sex and get some basic ancestry info – no genome-wide data on the Christians).

Muslim necropoleis (Loulé): ~95% local to Algarve baseline, a handful of non-locals compatible with Maghreb or SE Spain.
Christian necropolis (Cacela Velha, right after 1240 conquest by the Order of Santiago): small sample (n=19 adults with isotopes, I think), but ~47% non-local, more males than females. The non-local signatures cluster in two main areas according to the probabilistic maps:


Along the lower/middle Guadiana valley (so eastern Algarve + western Andalusia, basically the historic "Baja Andalucia" borderland).
"N/NE Iberian areas" – this is a broad zone in their isoscape that includes much of northern Portugal, Galicia, León, etc. (the paper stresses the maps have limitations in resolution for the far north/west because of fewer baseline samples there, but the signatures are clearly "Atlantic-facing" rather than Mediterranean or interior Castilian).


They explicitly frame this as evidence of a colonisation process led by military orders and settlers from the Kingdom of Portugal (many knights of the Order of Santiago in the Algarve campaign were Portuguese or Leonese-Galician), plus some from neighbouring border regions. No suggestion of massive input from central/southern Spain beyond the immediate Guadiana area.

As Ruderico said, this is just a snapshot of the very first Christian generation post-conquest. Later centuries saw continued north→south migration inside Portugal (well documented historically and visible in modern DNA + genealogy), which is why modern Algarvians are genetically very Portuguese, closer to Galicians than to Andalusians, and don’t stand out from the rest of the country.

So nothing here contradicts the broader picture of genetic homogenisation within Portugal and very limited net North African input in the south (the few Maghreb-origin Muslims were a tiny minority and many probably left).

Note: "N/NE" is the cautious scientific wording for what is functionally the northern/northwestern Iberian zone (Portugal + Galicia/León), not evidence of settlers from Toledo or Burgos. If the resolution were better or they wanted to be less precise, they could have just said "northern Portugal and adjacent regions", but they stuck to what the isoscapes strictly allow.

[Abaddon]

Great thread, camarada.

As Sebastianus said, i think it was already expected, but new data is always welcome.

[gixajo]

To clear up the doubts:

The study is primarily an isotope study (87Sr/86Sr, δ18O, δ34S) with updated Iberian isoscapes + machine learning for provenance assignment. They only did aDNA on a subset of the Muslim samples (to confirm genetic sex and get some basic ancestry info – no genome-wide data on the Christians).

Muslim necropoleis (Loulé): ~95% local to Algarve baseline, a handful of non-locals compatible with Maghreb or SE Spain.
Christian necropolis (Cacela Velha, right after 1240 conquest by the Order of Santiago): small sample (n=19 adults with isotopes, I think), but ~47% non-local, more males than females. The non-local signatures cluster in two main areas according to the probabilistic maps:


Along the lower/middle Guadiana valley (so eastern Algarve + western Andalusia, basically the historic "Baja Andalucia" borderland).
"N/NE Iberian areas" – this is a broad zone in their isoscape that includes much of northern Portugal, Galicia, León, etc. (the paper stresses the maps have limitations in resolution for the far north/west because of fewer baseline samples there, but the signatures are clearly "Atlantic-facing" rather than Mediterranean or interior Castilian).


They explicitly frame this as evidence of a colonisation process led by military orders and settlers from the Kingdom of Portugal (many knights of the Order of Santiago in the Algarve campaign were Portuguese or Leonese-Galician), plus some from neighbouring border regions. No suggestion of massive input from central/southern Spain beyond the immediate Guadiana area.

As Ruderico said, this is just a snapshot of the very first Christian generation post-conquest. Later centuries saw continued north→south migration inside Portugal (well documented historically and visible in modern DNA + genealogy), which is why modern Algarvians are genetically very Portuguese, closer to Galicians than to Andalusians, and don’t stand out from the rest of the country.

So nothing here contradicts the broader picture of genetic homogenisation within Portugal and very limited net North African input in the south (the few Maghreb-origin Muslims were a tiny minority and many probably left).

Note: "N/NE" is the cautious scientific wording for what is functionally the northern/northwestern Iberian zone (Portugal + Galicia/León), not evidence of settlers from Toledo or Burgos. If the resolution were better or they wanted to be less precise, they could have just said "northern Portugal and adjacent regions", but they stuck to what the isoscapes strictly allow.

Ok, so no more to add.:thumb001:

Thanks.