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

Seven date palm seeds (Phoenix dactylifera L.), radiocarbon dated from the fourth century BCE to the second century CE, were recovered from archaeological sites in the Southern Levant and germinated to yield viable plants. We conducted whole-genome sequencing of these germinated ancient samples and used single-nucleotide polymorphism data to examine the genetics of these previously extinct Judean date palms. We find that the oldest seeds from the fourth to first century BCE are related to modern West Asian date varieties, but later material from the second century BCE to second century CE showed increasing genetic affinities to present-day North African date palms. Population genomic analysis reveals that by -2,400 to 2,000 y ago, the P. dactylifera gene pool in the Eastern Mediterranean already contained introgressed segments from the Cretan palm Phoenix theophrasti, a crucial genetic feature of the modern North African date palm populations. The P. theophrasti introgression fraction content is generally higher in the later samples, while introgression tracts are longer in these ancient germinated date palms compared to modern North African varieties. These results provide insights into crop evolution arising from an analysis of plants originating from ancient germinated seeds and demonstrate what can be accomplished with the application of a resurrection genomics approach.

Automated summary

Researchers recovered seven date palm seeds from archaeological sites in the Southern Levant, dating from the fourth century BCE to the second century CE, which were germinated to yield viable plants. Whole-genome sequencing of these ancient samples showed genetic relationships between the ancient Judean date palms and modern West Asian and North African date palm varieties. These findings provide insights into crop evolution and the introgression of genetic features from the Cretan palm Phoenix theophrasti into modern North African date palm populations.