Abstract Detail

Hybrids and Hybridization

Ruiz, David Criado [1], Villa Machío, Irene [1], Nieto Feliner, Gonzalo [1].

Hybridization and cryptic speciation in the Iberian endemic plant genus Phalacrocarpum (Asteraceae-Anthemideae).

Since the frequency of natural hybridization is nowadays unquestionable, the hottest remaining debate concerning this process is whether hybridization is mostly a transient phenomenon that does not promote speciation or one that may promote, or be associated to, adaptation and diversification. Reconstructing evolutionary history of groups containing hybrid lineages, particularly ancient ones, contributes positively to this debate, but such reconstruction is not devoid of difficulties. Phalacrocarpum (DC.) Willk. is one of the 27 Iberian endemic plant genera, currently considered monotypic but including three subspecies: P. oppositifolium subsp. anomalum, subsp. hoffmannseggii and subsp. oppositifolium. Its persistent taxonomic instability have been proposed to be due to hybridization, which could also be involved in its uncertain phylogenetic relationships within tribe Anthemideae (Asteraceae). We have used SNPs, called from a genotyping-by-sequencing (GBS) analysis, Sanger sequences and leaf morphometric multivariatics to reconstruct the evolutionary history of this genus. Two findings are conclusive. SNP data and Sanger sequences strongly support the unforeseen existence of a cryptic species in the eastern populations of P. oppositifolium subsp. anomalum. Broad molecular and morphometric patterns of variation found in conflictive populations from the Sanabria Valley region identify a recent previously undocumented hybrid zone. However, evidences are less conclusive concerning relationships between subspecies hoffmannseggii, oppositifolium and a rather variable group of populations distributed along the Galician-Portuguese border (Orense massifs). Although genetic clustering analyses of SNP data suggest that the former subspecies was the maternal progenitor in hybridization events that gave rise to the other two groups, we found considerable uniqueness of ITS ribotypes and plastid haplotypes in them. This result, in the context of Pleistocene climatically-driven range shifts in NW Iberian Peninsula, can be due to periods of isolation and drift, superimposed on old hybridization events. Our study confirms the idea that unravelling old hybridization events may be compromised by the suite of evolutionary processes accumulated subsequently, particularly in areas with a history of climatic instability.

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1 - Real Jadrín Botánico de Madrid-CSIC, Biodiversity and conservation, Plaza de Murillo, 2, Madrid, Madrid, 28014, España

Keywords:
hybridization
Iberian Peninsula
Phalacrocarpum
Genotyping-by-sequencing
Morphometrics
cryptic species.

Presentation Type: Oral Paper
Session: HH2, Hybrids and Hybridization II
Location: /
Date: Wednesday, July 21st, 2021
Time: 1:15 PM(EDT)
Number: HH2004
Abstract ID:345
Candidate for Awards:Margaret Menzel Award