Lactase persistence and 13910*T in Iran:
The evolutionary genetics of lactase persistence in seven ethnic groups across the Iranian plateau (Charati et al. 2019)
"The LP (lactase persistence) frequency distribution ranged from 0 to 29.9% in the seven Iranian ethnic groups with an average value of 9.8%. The variants, − 13910*T and − 22018*A, were significantly associated with LP phenotype in Iranians. (...) Our results indicate the distribution of LP in seven ethnic groups across the Iranian plateau. Soft selective sweep rather than hard selective sweep played a substantial role in the evolution of LP in Iranian populations. (...)
The recent genetic screening for Iranians showed the occurrence of − 13910*T at 10%. The genotype-phenotype correlation was high, suggesting that − 13910*T might explain LP in Iranian population (…) The prevalence of − 13910*T was found in most populations (4.16–7.69%) with the exception of the Gilaks. (...)
All − 13910*T alleles were observed on haplotype A that is agreement with previous studies. (...)
In particular, the occurrence of − 13910*T in two distinguished LP haplotypes was observed in Iranians. Both haplotypes in Iranians were dated within 3000 years that was much later than the dairying practices spread from the West Asia to Europe, raising the possibility that the − 13910*T alleles might be introduced into Iran recently."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6371433/