Liv Borgen

• Gustafsson, A Lovisa S; Gussarova, Galina; Borgen, Liv; Ikeda, Hajime; Antonelli, Alexandre & Marie-Orleach, Lucas [Show all 8 contributors for this article] (2021). Rapid evolution of post-zygotic reproductive isolation is widespread in Arctic plant lineages. Annals of Botany. ISSN 0305-7364. 129(2), p. 171–184. doi: 10.1093/aob/mcab128. Full text in Research Archive Show summary

  Abstract Background and Aims The Arctic tundra, with its extreme temperatures and short growing season, is evolutionarily young and harbours one of the most species-poor floras on Earth. Arctic species often show little phenotypic and genetic divergence across circumpolar ranges. However, strong intraspecific post-zygotic reproductive isolation (RI) in terms of hybrid sterility has frequently evolved within selfing Arctic species of the genus Draba. Here we assess whether incipient biological species are common in the Arctic flora. Methods We conducted an extensive crossing experiment including six species representing four phylogenetically distant families collected across the circumpolar Arctic. We crossed conspecific parental populations representing different spatial scales, raised 740 F1 hybrids to maturity and measured fertility under laboratory conditions. We examined genetic divergence between populations for two of these species (Cardamine bellidifolia and Ranunculus pygmaeus). Key Results In five of the six species, we find extensive reduction in pollen fertility and seed set in F1 hybrids; 219 (46 %) of the 477 F1 hybrids generated between parents separated by ≥427 km had <20 % pollen fertility. Isolation with migration (IM) and *BEAST analyses of sequences of eight nuclear genes in C. bellidifolia suggests that reproductively isolated populations of this species diverged during, or even after, the last glaciation. Likewise, Arctic populations of R. pygmaeus were genetically very similar despite exhibiting strongly reduced fertility in crosses, suggesting that RI evolved recently also in this species. Conclusion We show that post-zygotic RI has developed multiple times within taxonomically recognized Arctic species belonging to several distantly related lineages, and that RI may have developed over just a few millennia. Rapid and widespread evolution of incipient biological species in the Arctic flora might be associated with frequent bottlenecks due to glacial cycles, and/or selfing mating systems, which are common in the harsh Arctic environment where pollinators are scarce.

• Borgen, Liv (2016). Årets plante, jåblom Parnassia palustris, sett fra et populasjonsgenetisk perspektiv. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 74(1), p. 7–11. Full text in Research Archive
• Gustafsson, A Lovisa S; Skrede, Inger; Rowe, Heather C.; Gussarova, Galina; Borgen, Liv & Rieseberg, Loren [Show all 8 contributors for this article] (2014). Genetics of cryptic speciation within an arctic Mustard, Draba nivalis. PLOS ONE. 9(4). doi: 10.1371/journal.pone.0093834. Full text in Research Archive Show summary

  Crossing experiments indicate that hybrid sterility barriers frequently have developed within diploid, circumpolar plant species of the genus Draba. To gain insight into the rapid evolution of postzygotic reproductive isolation in this system, we augmented the linkage map of one of these species, D. nivalis, and searched for quantitative trait loci (QTLs) associated with reproductive isolation. The map adds 63 new dominant markers to a previously published dataset of 31 co-dominant microsatellites. These markers include 52 amplified fragment length polymorphisms (AFLPs) and 11 sequence-specific amplified polymorphisms (SSAPs) based on retrotransposon sequence. 22 markers displaying transmission ratio distortion were further included in the map. We resolved eight linkage groups with a total map length of 894 cM. Significant genotype-trait associations, or quantitative trait loci (QTL), were detected for reproductive phenotypes including pollen fertility (4 QTLs), seed set (3 QTLs), flowering time (3 QTLs) and number of flowers (4 QTLs). Observed patterns of inheritance were consistent with the influence of both nuclear-nuclear interactions and chromosomal changes on these traits. All seed set QTLs and one pollen fertility QTL displayed underdominant effects suggestive of the involvement of chromosomal rearrangements in hybrid sterility. Interestingly, D. nivalis is predominantly self-fertilizing, which may facilitate the establishment of underdominant loci and contribute to reproductive isolation.

• Bendiksby, Mika; Tribsch, Andreas; Borgen, Liv; Travnicek, Pavel & Brysting, Anne Krag (2011). Allopolyploid origins of the Galeopsis tetraploids - revisiting Müntzing's classical textbook example using molecular tools. New Phytologist. ISSN 0028-646X. 191(4), p. 1150–1167. doi: 10.1111/j.1469-8137.2011.03753.x. Full text in Research Archive Show summary

  • Whole-genome duplication coupled with hybridization is of prime importance in plant evolution. Here we reinvestigate Müntzing's classical example of allopolyploid speciation; the first report of experimental synthesis of a naturally occurring allopolyploid species, Galeopsis tetrahit. • Various molecular markers (cpDNA, NRPA2, amplified fragment length polymorphisms (AFLPs)) and flow cytometry were surveyed in population samples of subgenus Galeopsis, including two allopolyploid species and their potential diploid parents. • The presence of two divergent copies of single-copy NRPA2 confirms the allopolyploid origins of G. tetrahit and Galeopsis bifida. However, the two allopolyploids do not share the same maternal genome, as originally suggested by Müntzing. The results support independent origins, but not recurrent formation, of the two allotetraploids. Data further indicate frequent gene flow and introgression within ploidy levels, but less so between ploidy levels. • Our results confirm and elaborate on Müntzing's classical conclusion about allopolyploid origins of G. tetrahit and G. bifida. We address questions of general interest within polyploidy research, such as recurrent formation, gene flow and introgression within and between ploidy levels.

• Borgen, Liv & Guldahl, Ane Senstad (2011). Great-granny's Garden: a living archive and a sensory garden. Biodiversity and Conservation. ISSN 0960-3115. 20(2), p. 441–449. doi: 10.1007/s10531-010-9931-9. Full text in Research Archive
• Marcussen, Thomas & Borgen, Liv (2011). Species delimitation in the Ponto-Caucasian Viola sieheana complex, based on evidence from allozymes, morphology, ploidy levels, and crossing experiments. Plant Systematics and Evolution. ISSN 0378-2697. 291(3-4), p. 183–196. doi: 10.1007/s00606-010-0377-z. Full text in Research Archive
• Borgen, Liv (2010). Lobularia, Flora of North America, Volume 7: Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press. ISSN 9780195318227. p. 597–598. Full text in Research Archive
• Fjellheim, Siri; Jørgensen, Marte Holten; Kjos, Mari & Borgen, Liv (2009). A molecular study of hybridization and homoploid hybrid speciation in Argyranthemum (Asteraceae) on Tenerife, the Canary Islands. Botanical journal of the Linnean Society. ISSN 0024-4074. 159(1), p. 19–31. doi: 10.1111/j.1095-8339.2008.00947.x. Full text in Research Archive
• Skrede, Inger; Borgen, Liv & Brochmann, Christian (2009). Genetic structuring in three closely related circumpolar plant species: AFLP versus microsatellite markers and high-arctic versus arctic-alpine distributions. Heredity. ISSN 0018-067X. 102(3), p. 293–302. doi: 10.1038/hdy.2008.120. Full text in Research Archive
• Fjellheim, Siri; Jørgensen, Marte Holten; Kjos, Mari & Borgen, Liv (2009). A molecular study of hybridization and homoploid hybrid speciation in Argyranthemum (Asteraceae) on Tenerife, the Canary Islands. Botanical journal of the Linnean Society. ISSN 0024-4074. 159(1), p. 19–31. Full text in Research Archive Show summary

  Examples of recurrent homoploid hybrid speciation are few. One often-cited example is Argyranthemum sundingii. This example includes two described species, A. lemsii and A. sundingii, resulting from reciprocal hybridization between A. broussonetii and A. frutescens on Tenerife. The four species and artificial F-1 and F-2 hybrids have previously been investigated morphologically and cytologically. Here, we examine population differentiation based on amplified fragment length polymorphism to get a better understanding of the genetic relationships among the species and the extent of hybridization. We aim to investigate if there is molecular support for treating the hybrid species as one taxon. Seven parental and four hybrid species populations (149 individuals) were analysed and we scored 85 polymorphic markers. A few (2-5) were private to each species but variably present and mostly rare. Our principal coordinate, STRUCTURE and BAPS analyses and AMOVA resulted in a clear separation of the parental species. The hybrid species were genetically less divergent but not identical. Our data indicate that hybridization and introgression are common in all these species on Tenerife and support the hypothesis that homoploid hybrid speciation has occurred repeatedly. Intrinsic post-zygotic barriers are notoriously weak in Argyranthemum and reproductive isolation and speciation result primarily from strong ecological selection. (C) 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 19-31.

• Skrede, Inger; Brochmann, Christian; Borgen, Liv & Rieseberg, LH (2008). Genetics of intrinsic postzygotic isolation in a circumpolar plant species, Draba Nivalis (Brassicaceae). Evolution. ISSN 0014-3820. 62, p. 1840–1851. doi: 10.1111/j.1558-5646.2008.00418.x. Full text in Research Archive
• Borgen, Liv (2007). Etnobotanikk. In Jørgensen, Per M. (Eds.), Botanikkens historie i Norge. Fagbokforlaget. ISSN 9788245004991. p. 116–123. Full text in Research Archive
• Borgen, Liv & Jørgensen, Per Magnus (2007). Schübeler, Frederik Christian. In Jørgensen, Per M. (Eds.), Botanikkens historie i Norge. Fagbokforlaget. ISSN 9788245004991. p. 349–351. Full text in Research Archive
• Grundt, Hanne Hegre; Kjølner, Siri; Borgen, Liv; Rieseberg, LH & Brochmann, Christian (2006). High biological species diversity in the arctic flora. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 103, p. 972–975. Full text in Research Archive
• Grundt, Hanne H.; Obermayer, Renate & Borgen, Liv (2005). Ploidal levels in the arctic-alpine polyploid Draba lactea (Brassicaceae) and its low-ploid relatives. Botanical journal of the Linnean Society. ISSN 0024-4074. 147, p. 333–347. Full text in Research Archive
• Marcussen, Thomas; Borgen, Liv & Nordal, Inger (2005). New distributional and molecular information call into question the systematic position of the West Asian Viola sintenisii (Violaceae). Botanical journal of the Linnean Society. ISSN 0024-4074. 147, p. 91–98. Full text in Research Archive
• Guldahl, AS; Gabrielsen, Tove M; Scheen, Anne-Cathrine; Borgen, Liv; Steen, SW & Spjelkavik, S [Show all 7 contributors for this article] (2005). The Saxifraga rivularis complex in Svalbard: Molecules, ploidy and morphology. Flora: Morphologie, Geobotanik, Oekophysiologie. ISSN 0367-2530. 200, p. 207–221. Full text in Research Archive
• Brochmann, Christian; Brysting, Anne Krag; Alsos, Inger Greve; Borgen, Liv; Grundt, Hanne Hegre & Scheen, Anne-Cathrine [Show all 7 contributors for this article] (2004). Polyploidy in arctic plants. Biological Journal of the Linnean Society. ISSN 0024-4066. 82, p. 521–536. Full text in Research Archive
• Borgen, Liv (2003). Parnassia palustris: a genetically diverse species in Scandinavia. Botanical journal of the Linnean Society. ISSN 0024-4074. 142, p. 347–372. Full text in Research Archive
• Borgen, Liv (2003). Genome organization in diploid hybrid species of Argyranthemum (Asteraceae) in the Canary Islands. Botanical journal of the Linnean Society. ISSN 0024-4074. 141, p. 491–501. Full text in Research Archive
• Borgen, Liv (2002). Clypeola maritima L., Sp. Pl.:62, 1 May 1753 = Lobularia maritima (L.) Desv. P.533 in: Cafferty, S. & Jarvis, C. E. (eds), Typification of Linnaean plant names in Brassicaceae (Cruciferae). Taxon. ISSN 0040-0262. 51, p. 529–537. Full text in Research Archive
• Hagen, Aslaug Ragnhild; Borgen, Liv; Elven, Reidar; Stabbetorp, Odd Egil & Brochmann, Christian (2002). The arctic-alpine polyploids Cerastium alpinum and C. nigrescens (Caryophyllaceae) in a sympatric situation: breakdown of species integrity? Plant Systematics and Evolution. ISSN 0378-2697. 230, p. 203–219. Full text in Research Archive
• Marcussen, Thomas; Borgen, Liv & Nordal, Inger (2001). Viola hirta (Violaceae) and its relatives in Norway. Nordic Journal of Botany (NJB). ISSN 0107-055X. 21(1), p. 5–17. Full text in Research Archive Show summary

  Viola hirta is widespread in most of Europe but rare in Norway, occurring in four isolated enclaves around the Oslo Fjord. Allozymic and morphological patterns of variation were studied in 320 individuals of Viola hirta (2n = 20) and its relatives V. collina (2n = 20), V. odorata (2n = 20), and V. suavis (2n = 40) from 22 Norwegian populations. Ongoing introgression from both V. collina and V. odorata, as hypothesised by several authors, was not supported by our data. All hybrids proved to be primary ones and, apparently, introgression is rare. However, allozyme markers suggested that V. hirta may have been affected by ancient introgression from V. collina and possibly also from the East European V. ambigua (2n = 40) during its evolutionary history. Geographical differentiation, presumably relatively recent and post-glacial, was evident in V. hirta. Variation occurred also between and within V. odorata populations, most likely a consequence of independent introductions by man. No variation was observed in V. collina or in V. suavis. A key to the Norwegian species of subsection Viola and their primary hybrids based on morphological characters is provided in Flora Nordica note No. 26.

• Guldahl, A. S.; Borgen, Liv & Nordal, Inger (2001). Variation in the Festuca brachyphylla (Poaceae) complex in Svalbard, elucidated by chromosome numbers and isozymes. Botanical journal of the Linnean Society. ISSN 0024-4074. 137, p. 107–126. Full text in Research Archive
• Grundt, Hanne Hegre; Borgen, Liv & Elven, Reidar (2001). Infraspecific variation in Cerastium alpinum s. lat. (Caryophyllaceae) in Central Norway. Nordic Journal of Botany (NJB). ISSN 0107-055X. 20(6), p. 641–653. Full text in Research Archive
• Borgen, Liv & Often, Anders (2001). Stellaria 11-15. In Jonsell, Bengt & Karlsson, T. (Ed.), Flora Nordica 2. The Bergius Foundation, The Royal Swedish Academy of Sciences, Stockholm.. p. 129–133. Full text in Research Archive
• Borgen, Liv; Berg, Rolf Y.; Sjølie, H.; Torvik, S.E. & Vejrup, K. (2000). Mating system variation in three species of flowering plants on Hovedøya, Oslo, Norway. Avhandlinger (Det Norske Videnskaps-Akademi). 1. Matematisk-Naturvitenskapelig Klasse. ISSN 0549-7019. 39, p. 67–74. Full text in Research Archive
• Brysting, Anne Krag & Borgen, Liv (2000). Isozyme analysis of the Cerastium alpinum-C. arcticum complex (Caryophyllaceae) supports a splitting of C. arcticum Lange. Plant Systematics and Evolution. ISSN 0378-2697. 220, p. 199–221. Full text in Research Archive
• Brochmann, Christian; Borgen, Liv & Stabbetorp, Odd Egil (2000). Multiple diploid hybrid speciation of the Canary Island endemic Argyranthermum sundingii (Asteraceae). Plant Systematics and Evolution. ISSN 0378-2697. 220, p. 77–92. Full text in Research Archive
• Marcussen, Thomas & Borgen, Liv (2000). Allozymic variation and relationships within Viola subsection Viola (Violaceae). Plant Systematics and Evolution. ISSN 0378-2697. 223, p. 29–57. Full text in Research Archive Show summary

  Allozyme markers from ten European taxa of Viola subsection Viola suggests that this group is allotetraploid, based on x=5. All taxa had distinct multilocus phenotypes except V. alba sspp. alba and scotophylla, which were identical and different from ssp. dehnhardtii. Variation was consistently higher in Mediterranean populations than in North European ones. Hybridisation seems extensive but putative F1 hybrids were distinctly less fertile than the parental species. Nevertheless, increased fertility in later-generation hybrids and shared band patterns among taxa indicate an important role of hybridisation and introgression in past and present evolution within the subsection. The octoploid V. ambigua shows affinity to V. hirta (tetraploid). The octoploid V. suavis probably originated from V. pyrenaica and other unidentified tetraploids, and high variability suggests polytopy or even polyphyly. The stoloniferous condition (series Flagellatae) seems to be primitive in the subsection but the reduction of stolons (series Eflagellatae) may have originated multiple times.

• Borgen, Liv (2000). Professor Schübelers plass i norsk hagebrukshistorie. In Moe, Dagfinn; Salvesen, Per Harald & Øvstedal, Dag Olav (Ed.), Historiske hager : en nordisk hagehistorisk artikkelsamling ved 100-årsfeiringen av Muséhagen i Bergen, mai 1999. Universitetet i Bergen. ISSN 9788241902611. p. 22–27. Full text in Research Archive
• Grundt, Hanne Hegre; Borgen, Liv & Elven, Reidar (1999). Aspects of reproduction in Cerastium alpinum on calcic and ultramafic soils in Central Norway. Nordic Journal of Botany (NJB). ISSN 0107-055X. 19, p. 447–453. Full text in Research Archive
• Borgen, Liv (1999). Genetic variation in Minuartia (Caryophyllaceae) in Svalbard. Nordic Journal of Botany (NJB). ISSN 0107-055X. 19, p. 179–192. Full text in Research Archive

View all works in NVA

• Borgen, Liv (2014). Botanisk hage 1814-2014. Historien om en hage. Forlaget Press. ISBN 9788275477048. 335 p. Full text in Research Archive
• Bjorå, Charlotte Sletten; Bjureke, Kristina; Borgen, Liv; Danielsen, Dag Inge; Ervik, Finn & Finnanger, Anne [Show all 8 contributors for this article] (2011). Botanisk hage. En oase i Oslo. Universitetet i Oslo. ISBN 9788279700258. 127 p. Full text in Research Archive
• Borgen, Liv (2008). Fjellhagen - Botanisk hages vakreste anlegg. Universitetet i Oslo. ISBN 9788279700081. 96 p. Full text in Research Archive
• Borgen, Liv (2006). Urtegleder - Krydderplanter i Urtehagen i Botanisk hage. Universitetet i Oslo. ISBN 9788279700074. 128 p. Full text in Research Archive
• Borgen, Liv (2004). Schübeler, Frederik Christian ("Fritz"), 1815-92, botaniker [biografi]. Kunnskapsforlaget. 2 p. Full text in Research Archive

View all works in NVA

• Borgen, Liv; Brochmann, Christian; Haraldsen, Kirsten Borse; Nordal, Inger & Pedersen, Oddvar (2019). Rolf Yngvar Berg 1925–2018. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 77(1), p. 24–30. Full text in Research Archive
• Haraldsen, Kirsten Borse; Pedersen, Oddvar; Borgen, Liv & Nordal, Inger (2019). Rolf Y. Berg – bibliografi. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 77(1), p. 30–34. Full text in Research Archive
• Nordal, Inger; Borgen, Liv; Haraldsen, Kirsten Borse & Pedersen, Oddvar (2019). Et «dypdykk» i et livslangt forsknings-engasjement: Rolf Y. Berg. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 77(1), p. 35–43. Full text in Research Archive
• Høiland, Klaus & Borgen, Liv (2018). Professor Frederik Christian Schübeler som feltbotaniker. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 76(1), p. 47–62. Full text in Research Archive
• Borgen, Liv (2017). Frederik Christian Schübelers virke i Botanisk hage på Tøyen under mottoet "Dyrk verdifuldere vekster". Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 75, p. 91–112. Full text in Research Archive
• Borgen, Liv (2015). Botanisk hage på Tøyen og Frederik Christian Schübelers betydning for norsk hagebruk. Lokalhistorisk magasin. ISSN 0802-8931. p. 4–9. Full text in Research Archive
• Borgen, Liv (2015). Bokanmeldelse: Praktverk om norske klosterplanter og norske middelalderklostre. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 73(253). Full text in Research Archive
• Borgen, Liv (2015). Intervju om veksthusene i Botanisk hage. [Radio]. NRK P2 "Ekko" - intervjuet fant sted i Botanisk hage. Full text in Research Archive
• Østhagen, Haavard & Borgen, Liv (2015). Årsmøte DnR i Stavanger 22.-23. mai 2015. Lapprosen. ISSN 1504-6702. 18(3), p. 26–27. Full text in Research Archive
• Borgen, Liv (2015). Botanisk hages historie. Full text in Research Archive
• Borgen, Liv (2014). Botanisk hage 1814-2014. St. Hallvard. ISSN 0036-2859. 2, p. 4–21. Full text in Research Archive
• Borgen, Liv (2014). Botanisk hage grunnlagt i 1814: Viktig for den unge nasjonen. Apollon : Forskningsmagasin for Universitetet i Oslo. ISSN 0803-6926. 2, p. 18–21. Full text in Research Archive
• Bendiksby, Mika; Tribsch, Andreas; Borgen, Liv; Travnicek, Pavel & Brysting, Anne Krag (2012). Revisiting Müntzing's classical textbook example of allotetraploid Galeopsis tetrahit - using molecular tools. Full text in Research Archive
• Gustafsson, A Lovisa S; Borgen, Liv; Gusarova, Galina & Brochmann, Christian (2011). Cryptic Speciation in Arctic Plants. Full text in Research Archive
• Gustafsson, A Lovisa S; Brochmann, Christian; Gusarova, Galina & Borgen, Liv (2011). Cryptic Speciation in the Arctic. Full text in Research Archive
• Gustafsson, A Lovisa S; Brochmann, Christian; Borgen, Liv & Gusarova, Galina (2010). High Biological Species Diversity in the Arctic Flora? Full text in Research Archive
• Gustafsson, A Lovisa S; Parisod, Christian; Schranz, Eric; Borgen, Liv; Gusarova, Galina & Brochmann, Christian (2010). Genetics of Intrinsic Postzygotic Isolation in Draba nivalis (Brassicaceae). Full text in Research Archive
• Borgen, Liv & Guldahl, Ane Senstad (2009). Great-Granny’s Garden – A Living Archive and a Sensory Garden. Full text in Research Archive
• Borgen, Liv (2009). Hva er et gresskar? Botanikk, systematikk og historikk. In Ulfeng, A & Ulfeng, I J (Ed.), Gresskar - mye mer enn Halloween - matglede og botanisk eventyr. Møklegaards Trykkeri AS. ISSN 9788230312629. p. 13–27. Full text in Research Archive
• Gustafsson, Lovisa; Borgen, Liv; Gusarova, Galina & Brochmann, Christian (2009). High Biological Species Diversity in the Arctic Flora? Full text in Research Archive
• Borgen, Liv (2009). Einer - den nyttigste planten i norsk natur? Norsk institutt for skog og landskap. Full text in Research Archive
• Skrede, Inger; Brochmann, Christian; Borgen, Liv & Rieseberg, Loren h (2008). Sibling speciation in the diploid, selfing Draba nivalis (Brassicaceae). Full text in Research Archive
• Borgen, Liv (2008). Verifisering av hasjplante. [Journal]. VG. Full text in Research Archive
• Borgen, Liv; Fjellheim, S & Kjos, Mari (2007). AFLP data confirm recurrent homoploid hybrid speciation in Argyranthemum (Asteraceae). Full text in Research Archive
• Skrede, Inger; Borgen, Liv; Brochmann, Christian & Rieseberg, Loren (2007). Sibling speciation in arctic diploid Draba (Brassicaceae). Full text in Research Archive
• Skrede, Inger; Borgen, Liv; Brochmann, Christian & Rieseberg, Loren (2007). Sibling speciation in arctic diploid Draba (Brassicaceae). Full text in Research Archive Show summary

  Incomplete to fully developed postzygotic sterility barriers within species were recently demonstrated in three circumpolar species of the genus Draba, suggesting numerous sibling species (Grundt et al., 2006; PNAS, 103, 972-975). Because the three species are selfers and of recent, Pleistocene origin, Grundt et al. argued that hybrid sterility evolved quickly and possibly by genetic drift. The present study employs genetic mapping and quantitative trait locus (QTL) analyses to determine whether the sterility has a chromosomal or genic basis and, if the latter, whether the sterility is caused by interactions among alleles at a single locus or by interactions among alleles at different loci. A F2 population of 383 individuals was generated by crossing two Draba nivalis plants, one from Alaska and one from Norway (F1 hybrids were ~30 % fertile). All F2 plants have been tested for pollen viability, seed set, and growth rate, and were on average 62 % fertile for the two fertility measures. A microsatellite-enriched library has been made for Draba, and 50 loci have been genotyped for all individuals. QTL analyses identified five loci underlying seed fertility and two affecting reduced pollen viability. Seed fertility QTLs were weakly underdominant, an observation most consistent with single locus sterility, such as that caused by chromosomal rearrangements. In contrast, pollen sterility QTLs exhibited additive inheritance patterns as might be expected for Dobzhansky-Muller incompatibilities. The small number of sterility QTLs is consistent with results from other plant groups, which imply that fewer loci contribute to hybrid sterility in plants than in Drosophila.

• Borgen, Liv (2006). Presentasjon av urtehagen i Botanisk hage. Full text in Research Archive
• Skrede, Inger; Borgen, Liv; Brochmann, Christian & Rieseberg, Loren (2006). The mechanisms of postzygotic reproductive isolation in Draba nivalis (Brassicaceae). Full text in Research Archive Show summary

  Incomplete to fully developed postzygotic sterility barriers within species were recently demonstrated in three circumpolar species of the genus Draba (Grundt et al., 2006; PNAS, 103, 972-975). Because the three species are selfers and of recent, Pleistocene origin, Grundt et al. argued that hybrid sterility evolved quickly and possibly by genetic drift. The present study employs a combination of QTL and meiotic analyses to determine whether the sterility has a chromosomal or genic basis and, if the latter, whether the sterility is caused by interactions among alleles at a single locus or by interactions among alleles at different loci. We have generated an F2 population of ~400 individuals by crossing Draba nivalis plants from Alaska and Norway (F1 hybrids were ~50% fertile). All F2 plants have been tested for pollen viability, seed set, and biomass. To genotype the F2 population, a microsatellite-enriched library has been made for Draba, and 60 microsatellites have been developed. So far, 23 markers have been analyzed for all individuals.

• Borgen, Liv (2006). Ex situ/ conservation and related activities in the Botanical Garden, Natural History Museum, University of Oslo. Full text in Research Archive
• Borgen, Liv (2005). Plantearven - vårt felles ansvar. Palmebladet. ISSN 1503-4593. 6, p. 6–8. Full text in Research Archive
• Obermayer, Renate; Grundt, Hanne Hegre & Borgen, Liv (2005). Ploidy patterns in the arctic-alpine polyploid Draba lactea Adams (Brassicaceae) and its low-ploid relatives. Full text in Research Archive
• Borgen, Liv; Jørgensen, Marte & Obermayer, Renate (2005). Why is it so difficult to obtain high quality AFLP profiles in Argyranthemum? Full text in Research Archive
• Borgen, Liv; Jørgensen, Marte Holten & Obermayer, Renate (2005). Why is it so difficult to obtain high quality AFLP profiles in Argyranthemum? Full text in Research Archive
• Borgen, Liv (2004). Rapport fra en studiereise. Palmebladet. ISSN 1503-4593. 4, p. 21–23. Full text in Research Archive
• Borgen, Liv (2004). Historien om et levende fossil, urtidstreet Metasequoia glyptostroboides. Blyttia : Norsk botanisk forenings tidsskrift. ISSN 0006-5269. 62, p. 63–66. Full text in Research Archive
• Borgen, Liv (2004). Fjellhagen - noen av høydepunktene i sommerhalvåret. Palmebladet. ISSN 1503-4593. 3, p. 3–5. Full text in Research Archive
• Borgen, Liv (2004). Botanisk hages bestyrer 1866-1892, Frederik Christian Schübeler. Palmebladet. ISSN 1503-4593. 4, p. 2–3. Full text in Research Archive
• Borgen, Liv (2004). Medisinplanter i norsk natur. Full text in Research Archive
• Borgen, Liv (2004). Planter til nytte og glede, død og fordervelse. Full text in Research Archive
• Obermayer, Renate; Grundt, Hanne Hegre & Borgen, Liv (2004). Monitoring ploidy patterns in arctic-alpine polyploid Draba lactea Adams (Brassicaceae) and its low-ploid relatives. Full text in Research Archive
• Brochmann, Christian; Brysting, Anne Krag; Grundt, Hanne Hegre; Borgen, Liv & Elven, Reidar (2003). Polyploidy in arctic plants. Full text in Research Archive
• Borgen, Liv (2003). Fjellhagen. Palmebladet. ISSN 1503-4593. 2, p. 3–6. Full text in Research Archive
• Borgen, Liv (2003). Conservation of important horticultural plants in European Botanic Gardens: a case study from Norway. Scripta Botanica Belgica. ISSN 0779-2387. p. 17–17. Full text in Research Archive
• Borgen, Liv (2003). Gresskar. Palmebladet. ISSN 1503-4593. 1, p. 11–12. Full text in Research Archive
• Borgen, Liv (2003). Gresskar og Halloween i Botanisk hage - mangfold og glede, grøss og gru. Palmebladet. ISSN 1503-4593. 1, p. 9–10. Full text in Research Archive
• Borgen, Liv (2003). Februarblomstring i Botanisk hage i Oslo. Norsk hagetidend : populært tidsskrift for hagedyrkere. ISSN 0029-1986. p. 81–81. Full text in Research Archive
• Grundt, Hanne Hegre; Popp, M.; Borgen, Liv; Elven, Reidar; Brochmann, Christian & Oxelman, B. (2002). The history of the circumpolar allopolyploid Draba lactea based on homoeologous nuclear DNA sequences. Full text in Research Archive
• Borgen, Liv (2002). Bevaring av plantegenetiske ressurser i klonarkiv. Full text in Research Archive
• Borgen, Liv (2002). Parnassia palustris: a genetically diverse species in Scandinavia. Full text in Research Archive
• Borgen, Liv (2002). Vår i Kew Gardens. Full text in Research Archive
• Borgen, Liv (2001). Fra naturens verden. [Radio]. Oslo. : Radioens P1.. Full text in Research Archive
• Borgen, Liv (2000). Dufthagen på Tøyen. Guidehefte til Botanisk hages 'Dufthage'. Botanisk hage og museum.. Full text in Research Archive
• Borgen, Liv (2000). The Rock Garden. Highlights. Selected atractions Natural History Museums and Botanical Garden.. p. 8–17. Full text in Research Archive
• Borgen, Liv (2000). Purpursolhatt, Echinacea purpurea. Botaniske Ark. 3. Full text in Research Archive
• Borgen, Liv (2000). Eseltistel, Onopordon acanthium. Botaniske Ark. 4. Full text in Research Archive
• Borgen, Liv (2000). Legeplanter i norsk flora. I. Våre nyttevekster. ISSN 0332-7280. 95, p. 54–61. Full text in Research Archive
• Borgen, Liv (2000). Legeplanter i norsk flora. II. Våre nyttevekster. ISSN 0332-7280. 95, p. 92–104. Full text in Research Archive
• Borgen, Liv (1999). Glimt fra humlens og humlehagenes historie i Norge. Våre nyttevekster. ISSN 0332-7280. 94, p. 45–56. Full text in Research Archive
• Borgen, Liv (1999). Professor Schübelers plass i norsk hagebrukshistorie. Full text in Research Archive
• Scheen, Anne-Cathrine; Brochmann, Christian; Spjelkavik, S.; Borgen, Liv & Elven, Reidar (1999). The Draba lactea/fladnizensis complex (Brassicaceae) in Svalbard: relationships and evolution within the group. Full text in Research Archive
• Bjureke, Kristina; Borgen, Liv; Finnanger, Anne & Skinnarland, Nils Ifver (2002). Gresskar - mangfold og glede, grøss og gru. Universitetets naturhistoriske museer og botaniske hage. Full text in Research Archive
• Borgen, Liv (2000). Kompendium i enzymelektroforese. Lab.-manual for BB 300, Botanikk, innføringskurs til hovedfag. [Oppdatert versjon.]. Universitetet i Oslo. Full text in Research Archive

View all works in NVA