Why do the Samaritans have high frequencies of Rh-blood?

Rh negative gene (cde) frequency among Samaritans: 42.9%

Recently several genetic studies on the Samaritan population were made using haplogroup comparisons as well as wide-genome genetic studies. Of the 12 Samaritan males used in the analysis, 10 (83%) had Y chromosomes belonging to haplogroup J, which includes three of the four Samaritan families. The Joshua-Marhiv family belongs to Haplogroup J-M267 (formerly “J1”), while the Danafi and Tsedakah families belong to haplogroup J-M172 (formerly “J2”), and can be further distinguished by the M67 SNP—the derived allele of which has been found in the Danafi family—and the PF5169 SNP found in the Tsedakah family. However the biggest and most important Samaritan family, the Cohen family (Tradition: Tribe of Levi), was found to belong to haplogroup E.

Blood types of the ancient Hebrews