Archaeogenomics of a ~2,100-year-old Egyptian leaf provides a new timestamp on date palm domestication

Abstract

The date palm (Phoenix dactylifera) has been a cornerstone of Middle Eastern and North African agriculture for millennia. It is presumed that date palms were first domesticated in the Persian Gulf and subsequently introduced into North Africa, where their evolution in the latter region appears to have been influenced by gene flow from the wild relative P. theophrasti, which is restricted to Crete and Turkey. However, the timing of gene flow from P. theophrasti to P. dactylifera remains unknown due to the limited archaeobotanical evidence of P. theophrasti and their exclusion from population genomic studies.We addressed this issue by investigating the relatedness and ancestry of a ~2,100-year-old P. dactylifera leaf from Saqqara (Egypt), combining genome sequencing of this ancient specimen with a broad sample of date palm cultivars and closely related species.The ancient Saqqara date palm shares close genetic ancestry with North African date palm populations. We find clear genomic admixture between the Saqqara date palm, P. theophrasti and the closest known relative P. sylvestris.Our study highlights that gene flow from P. theophrasti and P. sylvestris to North African date palms had already occurred at least ~2,100 years ago, providing a minimum timestamp for hybridisation between species.

The genomes of ancient date palms germinated from 2,000 y old seeds

“…From our analyses of the Judean date palms, it is apparent that by ∼2,400 to 2,000 y ago, the hybridization event(s) that introduced P. theophrasti genomic segments into the P. dactylifera cultivated gene pool had already occurred. This is also consistent with sequencing of an ancient date palm leaf from an archaeological excavation of a temple complex of the animal necropolis in Saqqara, Egypt, that dates to ∼2,100 y ago and which likewise shows P. theophrasti introgression (60).…”