%N 5
%V 116
%A JM Flowers
%A KM Hazzouri
%A M Gros-Balthazard
%A Z Mo
%A K Koutroumpa
%A A Perrakis
%A S Ferrand
%A HSM Khierallah
%A DQ Fuller
%A F Aberlenc
%A C Fournaraki
%A MD Purugganan
%T Cross-species hybridization and the origin of North African date palms
%D 2019
%P 1651-1658
%L discovery10069134
%K Science & Technology, Multidisciplinary Sciences, Science & Technology - Other Topics, introgression, archaeobotany, domestication, crop wild relative, range expansion, PHOENIX-DACTYLIFERA, PHYLOGENETIC ANALYSIS, GENETIC-STRUCTURE, HISTORY, ADMIXTURE, CULTIVATION, BEGINNINGS, EVOLUTION, REVEALS, CLIMATE
%J Proceedings of the National Academy of Sciences of The United States of America
%I NATL ACAD SCIENCES
%O This open access article is distributed under Creative Commons Attribution-NonCommercialNoDerivatives License 4.0 (CC BY-NC-ND).
%X Date palm (Phoenix dactylifera L.) is a major fruit crop of arid
regions that were domesticated =7,000 y ago in the Near or Middle
East. This species is cultivated widely in the Middle East and
North Africa, and previous population genetic studies have shown
genetic differentiation between these regions. We investigated
the evolutionary history of P. dactylifera and its wild relatives by
resequencing the genomes of date palm varieties and five of its
closest relatives. Our results indicate that the North African population
has mixed ancestry with components from Middle Eastern P.
dactylifera and Phoenix theophrasti, a wild relative endemic to the
Eastern Mediterranean. Introgressive hybridization is supported
by tests of admixture, reduced subdivision between North African
date palm and P. theophrasti, sharing of haplotypes in introgressed
regions, and a population model that incorporates gene
flow between these populations. Analysis of ancestry proportions
indicates that as much as 18% of the genome of North African varieties
can be traced to P. theophrasti and a large percentage of loci
in this population are segregating for single-nucleotide polymorphisms
(SNPs) that are fixed in P. theophrasti and absent from date
palm in the Middle East. We present a survey of Phoenix remains
in the archaeobotanical record which supports a late arrival of date
palm to North Africa. Our results suggest that hybridization with
P. theophrasti was of central importance in the diversification
history of the cultivated date palm.