Y-chromosome R-M343 African lineages and sickle cell disease reveal structured assimilation in Lebanon

Abstract

We have sought to identify signals of assimilation of African male lines in Lebanon by exploring the association of sickle cell disease (SCD) in Lebanon with Y-chromosome haplogroups that are informative of the disease origin and its exclusivity to the Muslim community. A total of 732 samples were analyzed, including 33 SCD patients from Lebanon genotyped for 28 binary markers and 19 short tandem repeats on the non-recombinant segment of the Y chromosome. Genetic organization was identified using populations known to have influenced the genetic structure of the Lebanese population, in addition to African populations with high incidence of SCD. Y-chromosome haplogroup R-M343 sub-lineages distinguish between sub-Saharan African and Lebanese Y chromosomes. We detected a limited penetration of SCD into Lebanese R-M343 carriers, restricted to Lebanese Muslims. We suggest that this penetration brought the sickle cell gene along with the African R-M343, probably with the Saharan caravan slave trade.

Figure 1

Sample distribution and Reduced Median Network of R-M343. The map shows the location of the samples used in the Networks and the respective color for every population. A) Reduced Median Network of R-M343 from all indicated populations in the map. B) Reduced Median Network of R-M343 from Lebanon, Central Africa and Lebanese Sickle Cell disease patients.

Figure 2

MDS plot of Φ distances between populations derived from Y-STR data of R-M343.

Figure 3

Reduced Median Networks of J-M267, J-M172, and E-M35.