title: Origins and domestication of cultivated banana inferred from chloroplast and nuclear genes.
abstract: BACKGROUND
  Cultivated bananas are large, vegetatively-propagated members of the genus Musa. More than 1,000 cultivars are grown worldwide and they are major economic and food resources in numerous developing countries. It has been suggested that cultivated bananas originated from the islands of Southeast Asia (ISEA) and have been developed through complex geodomestication pathways. However, the maternal and parental donors of most cultivars are unknown, and the pattern of nucleotide diversity in domesticated banana has not been fully resolved.
  
  
  RESULTS
  We studied the genetics of 16 cultivated and 18 wild Musa accessions using two single-copy nuclear (granule-bound starch synthase I, GBSS I, also known as Waxy, and alcohol dehydrogenase 1, Adh1) and two chloroplast (maturase K, matK, and the trnL-F gene cluster) genes. The results of phylogenetic analyses showed that all A-genome haplotypes of cultivated bananas were grouped together with those of ISEA subspecies of M. acuminata (A-genome). Similarly, the B- and S-genome haplotypes of cultivated bananas clustered with the wild species M. balbisiana (B-genome) and M. schizocarpa (S-genome), respectively. Notably, it has been shown that distinct haplotypes of each cultivar (A-genome group) were nested together to different ISEA subspecies M. acuminata. Analyses of nucleotide polymorphism in the Waxy and Adh1 genes revealed that, in comparison to the wild relatives, cultivated banana exhibited slightly lower nucleotide diversity both across all sites and specifically at silent sites. However, dramatically reduced nucleotide diversity was found at nonsynonymous sites for cultivated bananas.
  
  
  CONCLUSIONS
  Our study not only confirmed the origin of cultivated banana as arising from multiple intra- and inter-specific hybridization events, but also showed that cultivated banana may have not suffered a severe genetic bottleneck during the domestication process. Importantly, our findings suggested that multiple maternal origins and a reduction in nucleotide diversity at nonsynonymous sites are general attributes of cultivated bananas.
authors.affiliation: Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China ; Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Lin-Feng
authors.initials: LF
authors.lastname: Li
authors.forename: Hua-Ying
authors.initials: HY
authors.lastname: Wang
authors.forename: Cui
authors.initials: C
authors.lastname: Zhang
authors.forename: Xin-Feng
authors.initials: XF
authors.lastname: Wang
authors.forename: Feng-Xue
authors.initials: FX
authors.lastname: Shi
authors.forename: Wen-Na
authors.initials: WN
authors.lastname: Chen
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Ge
mesh_terms: D001210:Asia, Southeastern; D002736:Chloroplasts / Q000235:genetics*; D005787:Gene Frequency; D017343:Genes, Plant; D014644:Genetic Variation; D018745:Genome, Plant; D006239:Haplotypes; D006824:Hybridization, Genetic; D062312:Islands; D028521:Musa / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D011110:Polymorphism, Genetic; D013214:Starch Synthase / Q000235:genetics
chemical_list: D010940:Plant Proteins; C060756:waxy protein, plant; C434607:granule-bound starch synthase I; D013214:Starch Synthase