Macaronesia Acts as a Museum of Genetic Diversity of Relict Ferns: The Case of Diplazium caudatum (Athyriaceae)
Metadatos
Mostrar el registro completo del ítemAutor
Ben-Menni Schuler, Samira; Picazo Aragonés, Jesús; Romero García, Ana Teresa; Suárez Santiago, VíctorEditorial
MDPI
Materia
Fern phylogeography Genetic diversity Macaronesia Mating systems Microsatellites Plastid DNA Refugia Species distribution modelling Tertiary relicts
Fecha
2021Referencia bibliográfica
Schuler, S.B.-M.; Picazo-Aragonés, J.; Rumsey, F.J.; Romero-García, A.T.; Suárez-Santiago, V.N. Macaronesia Acts as a Museum of Genetic Diversity of Relict Ferns: The Case of Diplazium caudatum (Athyriaceae). Plants 2021, 10, 2425. https://doi.org/10.3390/plants 10112425
Resumen
Macaronesia has been considered a refuge region of the formerly widespread subtropical
lauroid flora that lived in Southern Europe during the Tertiary. The study of relict angiosperms
has shown that Macaronesian relict taxa preserve genetic variation and revealed general patterns
of colonization and dispersal. However, information on the conservation of genetic diversity and
range dynamics rapidly diminishes when referring to pteridophytes, despite their dominance of the
herbaceous stratum in the European tropical palaeoflora. Here we aim to elucidate the pattern of
genetic diversity and phylogeography of Diplazium caudatum, a hypothesized species of the Tertiary
Palaeotropical flora and currently with its populations restricted across Macaronesia and disjunctly in
the Sierras de Algeciras (Andalusia, southern Iberian Peninsula). We analysed 12 populations across
the species range using eight microsatellite loci, sequences of a region of plastid DNA, and carry out
species-distribution modelling analyses. Our dating results confirm the Tertiary origin of this species.
The Macaronesian archipelagos served as a refuge during at least the Quaternary glacial cycles, where
populations of D. caudatum preserved higher levels of genetic variation than mainland populations.
Our data suggest the disappearance of the species in the continent and the subsequent recolonization
from Macaronesia. The results of the AMOVA analysis and the indices of clonal diversity and
linkage disequilibrium suggest that D. caudatum is a species in which inter-gametophytic outcrossing
predominates, and that in the Andalusian populations there was a shift in mating system toward
increased inbreeding and/or clonality. The model that best explains the genetic diversity distribution
pattern observed in Macaronesia is, the initial and recurrent colonization between islands and
archipelagos and the relatively recent diversification of restricted area lineages, probably due to the
decrease of favorable habitats and competition with lineages previously established. This study
extends to ferns the concept of Macaronesia archipelagos as refugia for genetic variation.