Claim · model-written summary
Ks analyses indicated Xm divergence before polyploid formation at about 8.23 MYA.
- Taxon
- Leymus chinensisLeymus chinensist0
- Outcome
- Xm subgenome divergede0
- Value
- ~8.23 MYAe0
Not reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleTreatmentComparatorSettingDirectionQualifier
Verbatim
e0“the Xm subgenome diverged from its E-genome ancestor prior to polyploid formation (~8.23 MYA)”
t0“Leymus chinensis”
Title
Sijie Sun; Jianli Wang; Yu Guan; et al. Plant Biotechnology Journal 2026. doi:10.1111/pbi.70565
Other claims from this paper (19)
- Method / resource The updated L. chinensis assembly yielded two haplotypes of 7.96 Gb with 1121 and 1014 contigs.
- Method / resource Chromosome anchoring generated 28 pseudomolecules at over 96% anchoring.
- Method / resource The updated L. chinensis assemblies had improved contiguity and chromosomal completeness over the earlier reference.
- Method / resource The P. juncea genome assembly had two haplotypes of 6.33 and 6.38 Gb.
- Method / resource BUSCO assessments indicated high annotation completeness for both genomes.
- Observation Comparative genomics placed the L. chinensis and P. juncea Ns subgenomes in one clade.
- Observation Thinopyrum elongatum grouped with wheat ABD subgenomes.
- Observation Allotetraploidization was dated to about 6.35 MYA.
- Observation Subsequent Ns subgenome gene loss was dated to about 3.36 MYA.
- Observation S and Z loci were located on chromosomes 1Xm and 2Xm, respectively.
- Observation An HPS10II gene was identified outside the canonical Z locus.
- Observation DUF247I/II and HPS10 proteins showed haplotype discrimination.
- Observation DUF247 expression was stamen specific and HPS10 expression pistil specific in the Xm subgenome.
- Observation Synteny showed conserved flanking gene order.
- Observation Neither DUF247 nor HPS10 was detected in the Ns subgenome.
- Observation Brachypodium distachyon had more DUF247II-Z homologues, supporting an ancient Z locus.
- Observation DUF247 proteins in 101 accessions resolved four clades, with greater DUF247II-Z diversity.
- Observation Dating placed HPS10II emergence around 191 MYA, before DUF247I/II-Z around 150 MYA and DUF247I/II-S around 50 MYA.
- Mechanism The authors propose that an ancestral Z locus duplicated to generate S, followed by selective SI-gene loss from Ns.