Evolutionary dynamics of autopolyploids in natural populations: the case of Turnera sidoides complex

KOVALSKY, I EVELIN; ELIAS, G.; FERNÁNDEZ, S.A.; MORENO, E.M.S.; SILVA, G.C.; ROGGERO LUQUE, J.M.; ALMIRÓN, N.E.A.; SOLIS C.J.; DABRIO, A.; VIA DO PICO, GISELA M; SEIJO J.G.; VIVIANA GRISELDA SOLIS NEFFA

Journal of Basic & Applied Genetics

Sociedad Argentina de Genética

Año: 2022

Turnera sidoides (x=7) is one of the few well-studied South American autopolyploid complexes.Since polyploidy has played a prominent role within this complex, ongoing studies in T. sidoidesfocus on understanding the mechanisms involved in the origin and the establishment of polyploidsusing integrative approaches. This paper synthesises the results of more than 20 years of researchon this topic. Cytogenetics analysis provided evidences for the production of unreduced male andfemale gametes, supporting the hypothesis of bilateral sexual polyploidization as the mechanismof origin of polyploids in T. sidoides. The finding of viable triploids suggested that unilateralsexual polyploidization could also be an important mechanism for the origin of tetraploids in T.sidoides. The occurrence of plants continuously forming many unreduced gametes would play akey role in the establishment of neopolyploids in natural populations. Also, the higher numberof propagules that tetraploids contribute to subsequent generations, the ability to multiplyasexually by rhizomes, and the occurrence of occasional cases of self-compatibility and successfulillegitimate crosses in polyploids increase the likelihood that a low frequency of neopolyploids canbe maintained in natural populations of T. sidoides. In addition, integration of cytogeographic andgenetic divergence data together with past niche modelling provided further insights supportingthe hypothesis that historical climatic and geomorphological events provided favourableconditions for the establishment of autopolyploids, with the wider distribution of tetraploids of T.sidoides being the result of their range expansion.Key words: cytogeography, establishment, origin, polyploidy