title: A first genetic map of date palm (Phoenix dactylifera) reveals long-range genome structure conservation in the palms.
abstract: BACKGROUND
  The date palm is one of the oldest cultivated fruit trees. It is critical in many ways to cultures in arid lands by providing highly nutritious fruit while surviving extreme heat and environmental conditions. Despite its importance from antiquity, few genetic resources are available for improving the productivity and development of the dioecious date palm. To date there has been no genetic map and no sex chromosome has been identified.
  
  
  RESULTS
  Here we present the first genetic map for date palm and identify the putative date palm sex chromosome. We placed ~4000 markers on the map using nearly 1200 framework markers spanning a total of 1293 cM. We have integrated the genetic map, derived from the Khalas cultivar, with the draft genome and placed up to 19% of the draft genome sequence scaffolds onto linkage groups for the first time. This analysis revealed approximately ~1.9 cM/Mb on the map. Comparison of the date palm linkage groups revealed significant long-range synteny to oil palm. Analysis of the date palm sex-determination region suggests it is telomeric on linkage group 12 and recombination is not suppressed in the full chromosome.
  
  
  CONCLUSIONS
  Based on a modified genotyping-by-sequencing approach we have overcome challenges due to lack of genetic resources and provide the first genetic map for date palm. Combined with the recent draft genome sequence of the same cultivar, this resource offers a critical new tool for date palm biotechnology, palm comparative genomics and a better understanding of sex chromosome development in the palms.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Mathew
authors.forename: Manuel
authors.initials: M
authors.lastname: Spannagl
authors.forename: Ameena
authors.initials: A
authors.lastname: Al-Malki
authors.forename: Binu
authors.initials: B
authors.lastname: George
authors.forename: Maria F
authors.initials: MF
authors.lastname: Torres
authors.forename: Eman K
authors.initials: EK
authors.lastname: Al-Dous
authors.forename: Eman K
authors.initials: EK
authors.lastname: Al-Azwani
authors.forename: Emad
authors.initials: E
authors.lastname: Hussein
authors.forename: Sweety
authors.initials: S
authors.lastname: Mathew
authors.forename: Klaus F X
authors.initials: KF
authors.lastname: Mayer
authors.forename: Yasmin Ali
authors.initials: YA
authors.lastname: Mohamoud
authors.forename: Karsten
authors.initials: K
authors.lastname: Suhre
authors.affiliation: Genomics Laboratory, Weill Cornell Medical College in Qatar, Qatar Foundation, Doha, Qatar. jom2042@qatar-med.cornell.edu.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Malek
mesh_terms: D028023:Arecaceae / Q000235:genetics*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D030541:Databases, Genetic; D019143:Evolution, Molecular; D008040:Genetic Linkage; D018745:Genome, Plant; D023281:Genomics; D005838:Genotype; D020641:Polymorphism, Single Nucleotide; D012730:Sex Chromosomes
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