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The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio(Asteraceae)

The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio(Asteraceae)
The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio(Asteraceae)
Ecological speciation, driven by adaptation to contrasting environments, provides an attractive opportunity to study the formation of distinct species, and the role of selection and genomic divergence in this process. Here, we focus on a particularly clear-cut case of ecological speciation to reveal the genomic bases of reproductive isolation and morphological differences between closely related Senecio species, whose recent divergence within the last ~200 000 years was likely driven by the uplift of Mt. Etna (Sicily). These species form a hybrid zone, yet remain morphologically and ecologically distinct, despite active gene exchange. Here, we report a high-density genetic map of the Senecio genome and map hybrid breakdown to one large and several small quantitative trait loci (QTL). Loci under diversifying selection cluster in three 5 cM regions which are characterized by a significant increase in relative (FST), but not absolute (dXY), interspecific differentiation. They also correspond to some of the regions of greatest marker density, possibly corresponding to ‘cold-spots’ of recombination, such as centromeres or chromosomal inversions. Morphological QTL for leaf and floral traits overlap these clusters. We also detected three genomic regions with significant transmission ratio distortion (TRD), possibly indicating accumulation of intrinsic genetic incompatibilities between these recently diverged species. One of the TRD regions overlapped with a cluster of high species differentiation, and another overlaps the large QTL for hybrid breakdown, indicating that divergence of these species may have occurred due to a complex interplay of ecological divergence and accumulation of intrinsic genetic incompatibilities.
adaptation, genomic divergence, hybrid breakdown, senecio, speciation
1010-061X
98-113
Chapman, M.A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383
Hiscock, S.J.
fecab9dd-719b-47db-a0c9-bb2e45d09e9a
Filatov, D.A.
21d3492c-d49f-4283-997c-0176881b305e
Chapman, M.A.
8bac4a92-bfa7-4c3c-af29-9af852ef6383
Hiscock, S.J.
fecab9dd-719b-47db-a0c9-bb2e45d09e9a
Filatov, D.A.
21d3492c-d49f-4283-997c-0176881b305e

Chapman, M.A., Hiscock, S.J. and Filatov, D.A. (2016) The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio(Asteraceae). Journal of Evolutionary Biology, 29 (1), 98-113. (doi:10.1111/jeb.12765).

Record type: Article

Abstract

Ecological speciation, driven by adaptation to contrasting environments, provides an attractive opportunity to study the formation of distinct species, and the role of selection and genomic divergence in this process. Here, we focus on a particularly clear-cut case of ecological speciation to reveal the genomic bases of reproductive isolation and morphological differences between closely related Senecio species, whose recent divergence within the last ~200 000 years was likely driven by the uplift of Mt. Etna (Sicily). These species form a hybrid zone, yet remain morphologically and ecologically distinct, despite active gene exchange. Here, we report a high-density genetic map of the Senecio genome and map hybrid breakdown to one large and several small quantitative trait loci (QTL). Loci under diversifying selection cluster in three 5 cM regions which are characterized by a significant increase in relative (FST), but not absolute (dXY), interspecific differentiation. They also correspond to some of the regions of greatest marker density, possibly corresponding to ‘cold-spots’ of recombination, such as centromeres or chromosomal inversions. Morphological QTL for leaf and floral traits overlap these clusters. We also detected three genomic regions with significant transmission ratio distortion (TRD), possibly indicating accumulation of intrinsic genetic incompatibilities between these recently diverged species. One of the TRD regions overlapped with a cluster of high species differentiation, and another overlaps the large QTL for hybrid breakdown, indicating that divergence of these species may have occurred due to a complex interplay of ecological divergence and accumulation of intrinsic genetic incompatibilities.

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More information

Accepted/In Press date: 18 September 2015
e-pub ahead of print date: 28 September 2015
Published date: January 2016
Additional Information: This is the peer reviewed version of the following article: Chapman, M. A., Hiscock, S. J. and Filatov, D. A. (2016), The genomic bases of morphological divergence and reproductive isolation driven by ecological speciation in Senecio (Asteraceae). Journal of Evolutionary Biology, 29: 98–113. doi: 10.1111/jeb.12765, which has been published in final form at 10.1111/jeb.12765. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Keywords: adaptation, genomic divergence, hybrid breakdown, senecio, speciation
Organisations: Centre for Biological Sciences

Identifiers

Local EPrints ID: 388410
URI: http://eprints.soton.ac.uk/id/eprint/388410
ISSN: 1010-061X
PURE UUID: a1905755-4c5c-4772-8899-e93d79f8f4d3
ORCID for M.A. Chapman: ORCID iD orcid.org/0000-0002-7151-723X

Catalogue record

Date deposited: 25 Feb 2016 09:32
Last modified: 17 Dec 2019 01:37

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