RT Journal Article
T1 Karyotype evolution in Helianthemum (Cistaceae): dysploidy, achiasmate meiosis and ecological specialization in H. squamatum, a true gypsophile
A1 Aparicio, Abelardo
A1 Escudero, Marcial
A1 Valdés Florido, Ana
A1 Pachón, Miguel
A1 Rubio, Encarnación
A1 Albaladejo, Rafael G.
A1 Martín Hernanz, Sara
A1 Pradillo Orellana, Mónica
AB Helianthemum squamatum is a specialist gypsophile, the only species of a recently diverged lineage in subgenus Helianthemum characterized by having the lowest chromosome number in the genus (n = 5). With the hypothesis of great genome reorganization in the lineage of H. squamatum, we (1) modelled the evolution of the chromosome number in the genus Helianthemum, (2) analysed the karyotype and the nuclear DNA content of H. squamatum and its sister species H. syriacum (n = 10) and (3) studied in detail the meiotic process of H. squamatum. Our analyses show that: (1) the rate of chromosome losses in the lineage that gave rise to H. squamatum is 100 times higher than in the genus as a whole; (2) compared to its sister species, H. squamatum has a more symmetric karyotype composed of longer metacentric chromosomes and retains c. 80% of its nuclear DNA content and (3) achiasmatic behaviour of chromosomes occurs during microsporogenesis despite full synapsis. Our results are in agreement with previous knowledge showing that reduced chromosome numbers in determinate lineages are found in short-lived species adapted to stressful environments, and we suggest that a combination of fewer chromosomes, a smaller genome, a shorter life cycle and the suppression of meiotic recombination can together contribute to the maintenance of those advantageous allelic combinations that makes H. squamatum a true gypsophile, enabling the individual plants to cope with the harshness imposed by dry gypsum soils.
PB Oxford University Press
SN 0024-4074
YR 2019
FD 2019
LK https://hdl.handle.net/20.500.14352/110976
UL https://hdl.handle.net/20.500.14352/110976
LA eng
NO Aparicio A, Escudero M, Valdés-Florido A, Pachón M, Rubio E, Albaladejo RG, Martín-Hernanz S, Pradillo M. Karyotype evolution in Helianthemum (Cistaceae): dysploidy, achiasmate meiosis and ecological specialization in H. squamatum, a true gypsophile. Botanical Journal of the Linnean Society 2019;191:484–501. https://doi.org/10.1093/botlinnean/boz066.
NO This research was funded by grants CGL2014-52459-P and CGL2017-82465-P from the Spanish Ministerio de Economía y Competitividad. Sara Martín-Hernanz is currently funded by the Spanish Secretaría de Estado de Investigación, Desarrollo e Innovación (Scholarship FPI, 2015).
NO Ministerio de Economía y Competitividad (España)
DS Docta Complutense
RD 26 dic 2025