Gibraltar
References
Plaza S, Calafell F, Helal A, Bouzerna N, Lefranc G, Bertranpetit J, Comas D. Joining the pillars of Hercules: mtDNA sequences show multidirectional gene flow in the western Mediterranean. Ann Hum Genet. 2003 Jul;67(Pt 4):312-28. PMID: 12914566
Bosch E, Calafell F, Comas D, Oefner PJ, Underhill PA, Bertranpetit J. High-resolution analysis of human Y-chromosome variation shows a sharp discontinuity and limited gene flow between northwestern Africa and the Iberian Peninsula. Am J Hum Genet. 2001 Apr;68(4):1019-29. PMID: 11254456
Comas D, Calafell F, Benchemsi N, Helal A, Lefranc G, Stoneking M, Batzer MA, Bertranpetit J, Sajantila A. Alu insertion polymorphisms in NW Africa and the Iberian Peninsula: evidence for a strong genetic boundary through the Gibraltar Straits. Hum Genet. 2000 Oct;107(4):312-9. PMID: 11129330