Recent Male-Mediated Gene Flow Over a Linguistic Barrier in Iberia, Suggested by Analysis of a Y-chromosomal DNA Polymorphism

Am J Hum Genet. 1999 Nov;65(5):1437-48. doi: 10.1086/302617.

Abstract

We have examined the worldwide distribution of a Y-chromosomal base-substitution polymorphism, the T/C transition at SRY-2627, where the T allele defines haplogroup 22; sequencing of primate homologues shows that the ancestral state cannot be determined unambiguously but is probably the C allele. Of 1,191 human Y chromosomes analyzed, 33 belong to haplogroup 22. Twenty-nine come from Iberia, and the highest frequencies are in Basques (11%; n=117) and Catalans (22%; n=32). Microsatellite and minisatellite (MSY1) diversity analysis shows that non-Iberian haplogroup-22 chromosomes are not significantly different from Iberian ones. The simplest interpretation of these data is that haplogroup 22 arose in Iberia and that non-Iberian cases reflect Iberian emigrants. Several different methods were used to date the origin of the polymorphism: microsatellite data gave ages of 1,650, 2,700, 3,100, or 3,450 years, and MSY1 gave ages of 1,000, 2,300, or 2,650 years, although 95% confidence intervals on all of these figures are wide. The age of the split between Basque and Catalan haplogroup-22 chromosomes was calculated as only 20% of the age of the lineage as a whole. This study thus provides evidence for direct or indirect gene flow over the substantial linguistic barrier between the Indo-European and non-Indo-European-speaking populations of the Catalans and the Basques, during the past few thousand years.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA-Binding Proteins / genetics
  • Ethnic Groups
  • Evolution, Molecular
  • Haplotypes
  • Humans
  • Language*
  • Male
  • Microsatellite Repeats / genetics
  • Molecular Sequence Data
  • Nuclear Proteins*
  • Polymerase Chain Reaction
  • Polymorphism, Genetic*
  • Polymorphism, Restriction Fragment Length
  • Sex-Determining Region Y Protein
  • Spain
  • Transcription Factors*
  • Y Chromosome / genetics*

Substances

  • DNA-Binding Proteins
  • Nsep1 protein, mouse
  • Nuclear Proteins
  • SRY protein, human
  • Sex-Determining Region Y Protein
  • Transcription Factors