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Multiple independent origins of intermediate species between Sorbus aucuparia and S. hybrida (Rosaceae) in the Baltic region

Levin, Joel LU ; Fay, Michael F.; Pellicer, Jaume and Hedrén, Mikael LU (2018) In Nordic Journal of Botany 36(12).
Abstract

Populations intermediate between the diploid and sexual Sorbus aucuparia and the tetraploid and facultative apomictic Sorbus hybrida are scattered in coastal regions of southern Scandinavia. Our aims were to investigate whether these populations were of local and independent origins, whether they were morphologically and molecularly distinct from each other and whether they could give rise to constant offspring by apomixis. Six intermediate populations from the Baltic Sea basin were studied for variation at nuclear and plastid microsatellite loci, for morphological differentiation patterns, and for ploidy level by flow cytometry. Seeds were sown to check for constancy with the mother plants. Three populations from Gotland and possibly... (More)

Populations intermediate between the diploid and sexual Sorbus aucuparia and the tetraploid and facultative apomictic Sorbus hybrida are scattered in coastal regions of southern Scandinavia. Our aims were to investigate whether these populations were of local and independent origins, whether they were morphologically and molecularly distinct from each other and whether they could give rise to constant offspring by apomixis. Six intermediate populations from the Baltic Sea basin were studied for variation at nuclear and plastid microsatellite loci, for morphological differentiation patterns, and for ploidy level by flow cytometry. Seeds were sown to check for constancy with the mother plants. Three populations from Gotland and possibly the small population from Uppland were in each case fixed for a unique combination of genetic markers, had restricted variation in leaf shape and were morphologically divergent from each other. Flow cytometry analysis showed that the four genetically monomorphic populations were consistently triploid. Cultivation showed that offspring from trees within two of the monomorphic populations had leaf shapes closely similar to the mother individuals. In contrast, a population from Gotland and a population from Åland were variable at molecular marker loci and were variable in leaf shape. The three monomorphic Gotland populations and possibly also the Uppland population propagate asexually by apomixis, and they have independent origins. The two variable populations are apparently composed of hybrids that have been formed repeatedly and independently between individuals of the two parental species growing at the same sites. One of the Gotland apomicts has already been described as Sorbus teodori. Sorbus faohraei Hedrén & J.Levin and Sorbus atrata Hedrén & J.Levin are described as new apomictic species from Gotland.

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author
organization
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Contribution to journal
publication status
published
subject
keywords
agamospermy, apomixis, endemism, hybridization, microsatellites, Scandinavia, Sorbus atrata, Sorbus faohraei
in
Nordic Journal of Botany
volume
36
issue
12
publisher
Board of the Nordic Journal of Botany
external identifiers
  • scopus:85059026153
ISSN
0107-055X
DOI
10.1111/njb.02035
language
English
LU publication?
yes
id
5733a4cb-fdbe-4348-91d7-b55847e85ed5
date added to LUP
2019-01-03 14:16:21
date last changed
2019-02-20 11:41:26
@article{5733a4cb-fdbe-4348-91d7-b55847e85ed5,
  abstract     = {<p>Populations intermediate between the diploid and sexual Sorbus aucuparia and the tetraploid and facultative apomictic Sorbus hybrida are scattered in coastal regions of southern Scandinavia. Our aims were to investigate whether these populations were of local and independent origins, whether they were morphologically and molecularly distinct from each other and whether they could give rise to constant offspring by apomixis. Six intermediate populations from the Baltic Sea basin were studied for variation at nuclear and plastid microsatellite loci, for morphological differentiation patterns, and for ploidy level by flow cytometry. Seeds were sown to check for constancy with the mother plants. Three populations from Gotland and possibly the small population from Uppland were in each case fixed for a unique combination of genetic markers, had restricted variation in leaf shape and were morphologically divergent from each other. Flow cytometry analysis showed that the four genetically monomorphic populations were consistently triploid. Cultivation showed that offspring from trees within two of the monomorphic populations had leaf shapes closely similar to the mother individuals. In contrast, a population from Gotland and a population from Åland were variable at molecular marker loci and were variable in leaf shape. The three monomorphic Gotland populations and possibly also the Uppland population propagate asexually by apomixis, and they have independent origins. The two variable populations are apparently composed of hybrids that have been formed repeatedly and independently between individuals of the two parental species growing at the same sites. One of the Gotland apomicts has already been described as Sorbus teodori. Sorbus faohraei Hedrén &amp; J.Levin and Sorbus atrata Hedrén &amp; J.Levin are described as new apomictic species from Gotland.</p>},
  articleno    = {e02035},
  author       = {Levin, Joel and Fay, Michael F. and Pellicer, Jaume and Hedrén, Mikael},
  issn         = {0107-055X},
  keyword      = {agamospermy,apomixis,endemism,hybridization,microsatellites,Scandinavia,Sorbus atrata,Sorbus faohraei},
  language     = {eng},
  number       = {12},
  publisher    = {Board of the Nordic Journal of Botany},
  series       = {Nordic Journal of Botany},
  title        = {Multiple independent origins of intermediate species between Sorbus aucuparia and S. hybrida (Rosaceae) in the Baltic region},
  url          = {http://dx.doi.org/10.1111/njb.02035},
  volume       = {36},
  year         = {2018},
}