In the comments section of the last post, Ricardo Costa de Oliveira alerts us to the possibility of a marker for the Alan migration from the Caucasus to the Iberian peninsula.
Ricardo points out that a specific J1b modal appears in two Iranians, as sited in the recent paper:
Influences of history, geography, and religion on genetic structure: the Marionites in Lebanon
Haber at al
(Figures and Tables)
(Lebanon by region, religion and sect)
(Iran by region)
Ricardo observes that two western Iranians, I171 and I174, bear the same model haplotype as some people from the Azores, Portugal and Brazil. Additionally, J1 haplotypes in the Iran table seem to be very diverse, confirming the results of Chiaroni et al indicating a Southeastern Turkey-Zagros Mountain origin of the J1 Haplogroup.
Given the documented westward migration of the Alans, it would not be out of the realm of possibility that this particular J1b haplotype marks that migration.
Research on Ossetians does not yet indicate this haplotype. It may have been lost in the centuries between the time of the Alan migrations westward and today.
In order to narrow in on which migration may have spread western Iranian haplotypes to the Iberian peninsula, it would be important to create a picture of Ossetian and western Iranian haplotypes to have reached western Europe and beyond.