Evolution of sex chromosomes prior to speciation in the dioecious Phoenix species.

Understanding the driving forces and molecular processes underlying dioecy and sex chromosome evolution, leading from hermaphroditism to the occurrence of male and female individuals, is of considerable interest in fundamental and applied research. The genus Phoenix, belonging to the Arecaceae family, consists uniquely of dioecious species. Phylogenetic data suggest that the genus Phoenix has diverged from a hermaphroditic ancestor which is also shared with its closest relatives.

Endemic insular and coastal Tunisian date palm genetic diversity.

The breeding of crop species relies on the valorisation of ancestral or wild varieties to enrich the cultivated germplasm. The Tunisian date palm genetic patrimony is being threatened by diversity loss and global climate change. We have conducted a genetic study to evaluate the potential of spontaneous coastal resources to improve the currently exploited Tunisian date palm genetic pool.

Genetic structure of the date palm (Phoenix dactylifera) in the Old World reveals a strong differentiation between eastern and western populations.

Background And Aims: Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecological value to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information on global genetic diversity and population structure. In order to contribute to the varietal improvement of date palms and to provide new insights on the influence of geographic origins and human activity on the genetic structure of the date palm, this study analysed the diversity of the species.

In silico mining of microsatellites in coding sequences of the date palm (Arecaceae) genome, characterization, and transferability.

Premise Of The Study: To complement existing sets of primarily dinucleotide microsatellite loci from noncoding sequences of date palm, we developed primers for tri- and hexanucleotide microsatellite loci identified within genes. Due to their conserved genomic locations, the primers should be useful in other palm taxa, and their utility was tested in seven other Phoenix species and in Chamaerops, Livistona, and Hyphaene. •

Methods And Results: Tandem repeat motifs of 3-6 bp were searched using a simple sequence repeat (SSR)-pipeline package in coding portions of the date palm draft genome sequence.

Male-specific DNA markers provide genetic evidence of an XY chromosome system, a recombination arrest and allow the tracing of paternal lineages in date palm.

Whether sex chromosomes are differentiated is an important aspect of our knowledge of dioecious plants, such as date palm (Phoenix dactylifera). In this crop plant, the female individuals produce dates, and are thus the more valuable sex. However, there is no way to identify the sex of date palm plants before reproductive age, and the sex-determining mechanism is still unclear.