Sequencing and assembly of high-quality complete genomes
Combined use of long-read technologies (PacBio HiFi, ultra-long Nanopore) and chromosome conformation capture (Hi-C, Pore-C)
Analysis of large populations in D. alata, D. trifida, D. esculenta, D. cayenensis, D. bulbifera, and D. dumetorum
Precise delineation of genomic regions controlling sex and confirmation of sex-determination systems
Study of sex chromosome turnover within the genus Dioscorea
Functional characterization of candidate genes using genetic transformation
Sex Determination Systems Diversity
Most cultivated yams are dioecious, bearing separate male and female plants. The genus Dioscorea displays a rare diversity of sex chromosome systems, including XY (D. alata, D. dumetorum, D. bulbifera, D. tokoro, and D. japonica), ZW (D. rotundata and D. deltoidea), and XO (D. reticulata and D. sinuata). This coexistence points to recurrent sex chromosome turnover throughout evolution.
Sex Lability and Monoecy
Spontaneous sex shifts (lability) and monoecious plants bearing both male and female flowers on the same individual have been documented in D. rotundata. The recent discovery of a fertile monoecious hybrid in D. alata demonstrates that this reproductive plasticity extends to other species. Consequently, sex expression appears to be modulated by key regulatory genes, extending beyond strict chromosomal control.
Chromosome Architecture
Genomic studies have identified specific sex-determining regions (SDRs). In D. alata, the SDR is located on chromosome 6 and harbors a major 7-Mb inversion on the Y chromosome that suppresses recombination. These features, characteristic of young sex chromosomes, make yams a prime model for evolutionary biology.
Sex chromosome: ND
System : XX / XY
Sex chromosome : ND
System : ND
Sex chromosome : ND
System : ND
Sex chromosome : ND
System : XX / XY
*ND : Not Determined
Find here the work associated with EvoSexYam, the publication of our articles in scientific journals, and key highlights from our research network.
The identification of the first documented case of monoecy and sex lability in the greater yam (Dioscorea alata) hybrid CIRAD187 challenges the long-held assumption of strict dioecy in this critical food security crop.
Characterization of the genome of the wild dioecious yam (Dioscorea tokoro) has shed light on the chromosomal architecture governing sex determination in this model species for evolutionary biology.
The assembly of the first reference genome for white Guinea yam (Dioscorea rotundata, 405 Mb) has unveiled the genetic mechanisms governing sex determination in this major staple crop.
This study provides a complete, haplotype-resolved genome assembly of a male greater yam (Dioscorea alata) cultivar, shedding new light on the sexual genetics of this crop :
The EvoSexYam project relies on an international network of partners who characterize the sexual phenotype of their yam collections and provide biological material for analysis. This synergy enables the acquisition of key genomic and transcriptomic data to decode the genetics of sex in these species.
Agence Nationale de la Recherche
Centre de coopération Internationale en Recherche Agronomique pour le Développement
Déterminisme et Expression des traits d’Intérêts chez les racines et tubercules
Université des Antilles
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
Centre National de Recherche Agronomique
Institut Togolais de Recherche Agronomique
International Institute of Tropical Agriculture
Vanuatu Agricultural Research and Technical Center
Centre des Tubercules Tropicaux du Technopole Nouvelle-Calédonie
Naoroji Godrej Centre for Plant Research
Benagen
Cirad, Station de Roujol
97170 Petit-Bourg
Guadeloupe
