Basque populations carry the RH-negative gene (the RHD deletion) at a frequency above 50%: Cavalli-Sforza et al. (1994) note that the Basques have 'more than 50% RH-negative genes', and a 2004 PCR study of 127 French Basques found an RH D-deletion frequency of 0.511, 'exceeding 0.50, as typically described from several decades'. This is a gene frequency, not the share of people who are Rh-negative. The source's 'world's highest' and '~25-35%' phenotype figure are held separately.
Evidence
| Relation | Record | Note |
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| documents | books.google.com | Cavalli-Sforza, Menozzi & Piazza, The History and Geography of Human Genes (Princeton UP 1994), Google Books search-inside snippet fetched directly 2026-10-04, p. 132: '… Basques, has more than 50% RH-negative genes' (snippet truncated before the subject) |
| documents | eutils.ncbi.nlm.nih.gov | Touinssi et al., Hum Hered 2004;58(2):69-72 (PMID 15711086) abstract: 127 French Basques; 'A high frequency of RH Ddel exceeding 0.50, as typically described from several decades, was found here (0.511)' |
Sources
Ties
Tied from
Claim
Basque populations carry the RH-negative gene (the RHD deletion) at a frequency above 50%: Cavalli-Sforza et al. (1994) note that the Basques have 'more than 50% RH-negative genes', and a 2004 PCR study of 127 French Basques found an RH D-deletion frequency of 0.511, 'exceeding 0.50, as typically described from several decades'. This is a gene frequency, not the share of people who are Rh-negative. The source's 'world's highest' and '~25-35%' phenotype figure are held separately.
Held separately: Basques have the world's highest Rh-negative blood frequency (~25-35%).