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Geographical isolation, habitat shifts and hybridisation in the diversification of the Macaronesian endemic genus Argyranthemum (Asteraceae)

Geographical isolation, habitat shifts and hybridisation in the diversification of the Macaronesian endemic genus Argyranthemum (Asteraceae)
Geographical isolation, habitat shifts and hybridisation in the diversification of the Macaronesian endemic genus Argyranthemum (Asteraceae)

Inferring the processes responsible for the rich endemic diversity of oceanic island floras is important for our understanding of plant evolution and setting practical conservation priorities. This requires an accurate knowledge of phylogenetic relationships, which have often been difficult to resolve due to a lack of genetic variation. We employed genotyping-by-sequencing (GBS) to investigate how geographical isolation, habitat shifts, and hybridisation have contributed to the evolution of diversity observed in Argyranthemum Webb (Asteraceae), the largest genus of flowering plants endemic to the Macaronesian archipelagos. Species relationships were resolved, and biogeographical stochastic mapping identified intra-island speciation as the most frequent biogeographic process underlying diversification, contrary to the prevailing view in Argyranthemum and the Canary Islands. D-statistics revealed significant evidence of hybridisation between lineages co-occurring on the same island, however there was little support for the hypothesis that hybridisation may be responsible for the occurrence of nonmonophyletic multi-island endemic (MIE) species. Geographic isolation, habitat shifts and hybridisation have all contributed to the diversification of Argyranthemum, with intra-island speciation found to be more frequent than previously thought. Morphological convergence is also proposed to explain the occurrence of nonmonophyletic MIE species. This study reveals greater complexity in the evolutionary processes generating Macaronesian endemic diversity.

Argyranthemum, Macaronesia, biogeographic stochastic mapping, biogeography, genotyping-by-sequencing, hybridisation, morphological convergence, speciation
0028-646X
1953–1971
White, Oliver W.
c36304a9-9881-40d4-bfca-e5c0bd48bdaa
Reyes‐betancort, J. Alfredo
2edaf647-f27c-4be9-8150-27b72d9aed64
Chapman, Mark A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383
Carine, Mark A.
eeaed5aa-bc4b-43ec-a667-b6c45e3217ed
White, Oliver W.
c36304a9-9881-40d4-bfca-e5c0bd48bdaa
Reyes‐betancort, J. Alfredo
2edaf647-f27c-4be9-8150-27b72d9aed64
Chapman, Mark A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383
Carine, Mark A.
eeaed5aa-bc4b-43ec-a667-b6c45e3217ed

White, Oliver W., Reyes‐betancort, J. Alfredo, Chapman, Mark A. and Carine, Mark A. (2020) Geographical isolation, habitat shifts and hybridisation in the diversification of the Macaronesian endemic genus Argyranthemum (Asteraceae). New Phytologist, 228 (6), 1953–1971. (doi:10.1111/nph.16980).

Record type: Article

Abstract

Inferring the processes responsible for the rich endemic diversity of oceanic island floras is important for our understanding of plant evolution and setting practical conservation priorities. This requires an accurate knowledge of phylogenetic relationships, which have often been difficult to resolve due to a lack of genetic variation. We employed genotyping-by-sequencing (GBS) to investigate how geographical isolation, habitat shifts, and hybridisation have contributed to the evolution of diversity observed in Argyranthemum Webb (Asteraceae), the largest genus of flowering plants endemic to the Macaronesian archipelagos. Species relationships were resolved, and biogeographical stochastic mapping identified intra-island speciation as the most frequent biogeographic process underlying diversification, contrary to the prevailing view in Argyranthemum and the Canary Islands. D-statistics revealed significant evidence of hybridisation between lineages co-occurring on the same island, however there was little support for the hypothesis that hybridisation may be responsible for the occurrence of nonmonophyletic multi-island endemic (MIE) species. Geographic isolation, habitat shifts and hybridisation have all contributed to the diversification of Argyranthemum, with intra-island speciation found to be more frequent than previously thought. Morphological convergence is also proposed to explain the occurrence of nonmonophyletic MIE species. This study reveals greater complexity in the evolutionary processes generating Macaronesian endemic diversity.

Text
NPH-MS-2020-33220.R1_Proof_fl - Accepted Manuscript
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Accepted/In Press date: 16 September 2020
e-pub ahead of print date: 2 October 2020
Published date: December 2020
Keywords: Argyranthemum, Macaronesia, biogeographic stochastic mapping, biogeography, genotyping-by-sequencing, hybridisation, morphological convergence, speciation

Identifiers

Local EPrints ID: 445209
URI: http://eprints.soton.ac.uk/id/eprint/445209
ISSN: 0028-646X
PURE UUID: 84d78595-efea-4140-914c-14cc50a1b166
ORCID for Mark A. Chapman: ORCID iD orcid.org/0000-0002-7151-723X

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Date deposited: 25 Nov 2020 17:31
Last modified: 17 Mar 2024 06:06

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Contributors

Author: Oliver W. White
Author: J. Alfredo Reyes‐betancort
Author: Mark A. Chapman ORCID iD
Author: Mark A. Carine

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