Speaker
Description
Polyploidy and hybridisation are important driving forces for angiosperm evolution but pose a challenge for sexual reproduction, as correct meiotic chromosome pairing needs to be established. The odd-ploid widespread European dogroses (Rosa sect. Caninae, 2n = 5x = 35) overcame hybrid sterility by evolving a unique meiosis mechanism: During Canina meiosis two chromosome sets form bivalents and are transmitted to both egg and sperm cells, while the remaining three chromosome sets are transmitted as univalents only via the egg cells. Thus, dogroses combine sexual and apomictic reproduction within the very same nucleus. Chromosome-level analyses of dogrose genomes in comparison with single copy gene data from dogrose pollen and diploid species across the genus Rosa revealed that dogroses are complex hybrids. Moreover, bivalent-forming chromosome sets exhibit distinct synteny but their evolutionary origin differed between dogrose clades indicating the multiple origin of the peculiar meiosis. We found that bivalent- and univalent forming chromosomes differed by their centromere size and composition irrespective of their evolutionary origin. A rose-specific satellite repeat dominates the univalent-forming chromosomes and thus probably contributes to their meiotic drive in the female germ line.
| Status Group | Senior Scientist |
|---|---|
| Poster Presentation Option | Yes, I’m willing to present as a poster. |
