Evolutionary genomics of peach and almond domestication

Authors: VELASCO, DIANNE - University Of California; HOUGH, JOSH - University Of California; Aradhya, Mallikarjuna; ROSS-IBARRA, JEFFREY - University Of California

Submitted to: Genes, Genomes, and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2016
Publication Date: 10/4/2016
Citation: Velasco, D., Hough, J., Aradhya, M.K., Ross-Ibarra, J. 2016. Evolutionary genomics of peach and almond domestication. Genes, Genomes, and Genomics. 6(12):3985-3993.

Interpretive Summary: The domesticated almond [Prunus dulcis (L.) Batsch] and peach [P. persica (Mill.) D. A. Webb] originate on opposite sides of Asia and were independently domesticated approximately 5000 years ago. While interfertile, they possess alternate mating systems and dier in a number of morphological and physiological traits. Here we evaluated thirteen resequenced genomes of both almond and peach for signatures of selection and to better understand their relationship. Almond has ~7X the genetic diversity of peach and high genome-wide FST values support their status as separate species. We estimated a divergence time of approximately 8 Mya, coinciding with an active period of uplift in the northeast Tibetan Plateau and subsequent Asian climate change. We identify a number of regions in both genomes showing signatures of selection during domestication, and a significant overlap in candidate regions between peach and almond. While we expected gene expression in fruit to overlap with candidate selected regions, instead we find enrichment for loci highly dierentiated between the species, consistent with recent fossil evidence suggesting fruit divergence long preceded domestication. Taken together this study tells us how closely related tree species evolve and are domesticated, the impact of these events on their genomes, and the utility of genomic information for long-lived species. Further exploration of this data will contribute to the genetic knowledge of these species and provide information regarding targets of selection for breeding application and further the understanding of evolution in these species.

Technical Abstract: The domesticated almond [Prunus dulcis (L.) Batsch] and peach [P. persica (Mill.) D. A. Webb] originate on opposite sides of Asia and were independently domesticated approximately 5000 years ago. While interfertile, they possess alternate mating systems and dier in a number of morphological and physiological traits. Here we evaluated thirteen resequenced genomes of both almond and peach for signatures of selection and to better understand their relationship. Almond has ~7X the genetic diversity of peach and high genome-wide FST values support their status as separate species. We estimated a divergence time of approximately 8 Mya, coinciding with an active period of uplift in the northeast Tibetan Plateau and subsequent Asian climate change. We identify a number of regions in both genomes showing signatures of selection during domestication, and a significant overlap in candidate regions between peach and almond. While we expected gene expression in fruit to overlap with candidate selected regions, instead we find enrichment for loci highly dierentiated between the species, consistent with recent fossil evidence suggesting fruit divergence long preceded domestication. Taken together this study tells us how closely related tree species evolve and are domesticated, the impact of these events on their genomes, and the utility of genomic information for long-lived species. Further exploration of this data will contribute to the genetic knowledge of these species and provide information regarding targets of selection for breeding application and further the understanding of evolution in these species.