Origins and geographic diversification of African rice (Oryza glaberrima)

Origins and geographic diversification of African rice (Oryza glaberrima)

| Margaretha A. Veltman, Jonathan M. Flowers, Tinde R. van Andel, M. Eric Schranz
This study re-evaluates the origins and geographic diversification of African rice (*Oryza glaberrima*) using whole genome sequences of 206 domesticated and wild accessions. The results support a severe bottleneck caused by domestication, but do not identify clear candidate domestication genes, suggesting that domestication may have proceeded differently from Asian rice. Population structure analysis reveals five genetic clusters localized to different geographic regions, with isolation by distance observed in coastal populations. Genome-wide phylogenetic relationships indicate an origin in the eastern cultivation range followed by diversification along the Atlantic coast. However, distinct haplotypes in the southwest suggest that at least one key domestication trait may have originated there. These findings challenge the commonly accepted centric origin of African rice, favoring a non-centric or polycentric view. The study highlights the divergent roots of African rice cultivation, including a separate center of domestication activity in the Guinea Highlands, and emphasizes the need to reconsider the traditional centric model.This study re-evaluates the origins and geographic diversification of African rice (*Oryza glaberrima*) using whole genome sequences of 206 domesticated and wild accessions. The results support a severe bottleneck caused by domestication, but do not identify clear candidate domestication genes, suggesting that domestication may have proceeded differently from Asian rice. Population structure analysis reveals five genetic clusters localized to different geographic regions, with isolation by distance observed in coastal populations. Genome-wide phylogenetic relationships indicate an origin in the eastern cultivation range followed by diversification along the Atlantic coast. However, distinct haplotypes in the southwest suggest that at least one key domestication trait may have originated there. These findings challenge the commonly accepted centric origin of African rice, favoring a non-centric or polycentric view. The study highlights the divergent roots of African rice cultivation, including a separate center of domestication activity in the Guinea Highlands, and emphasizes the need to reconsider the traditional centric model.
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