Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata

Many of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent model system in which to study the roles of demographic history and local adaptation in patterning genetic variation.We studied nucleotide diversity in six natural populations of Arabidopsis lyrata, using 77 loci sampled from 140 chromosomes. The six populations were highly differentiated, with a median FST of 0.52, and structure analysis revealed no evidence of admixed individuals. Average within-population diversity varied among populations, with the highest diversity found in a German population; this population harbors 3-fold higher levels of silent diversity than worldwide samples of A. thaliana. All A. lyrata populations also yielded positive values of Tajima's D. We estimated a demographic model for these populations, finding evidence of population divergence over the past 19,000 to 47,000 years involving non-equilibrium demographic events that reduced the effective size of most populations. Finally, we used the inferred demographic model to perform an initial test for local adaptation and identified several genes, including the flowering time gene FCA and a disease resistance locus, as candidates for local adaptation events.Our results underscore the importance of population-specific, non-equilibrium demographic processes in patterning diversity within A. lyrata. Moreover, our extensive dataset provides an important resource for future molecular population genetic studies of local adaptation in A. lyrata

Die Ambivalenzen der Schülerpartizipation - Partizipationsmaße und Sinnstrukturen der Partizipation im Vergleich

Helsper W, Böhm-Kasper O, Sandring O. Die Ambivalenzen der Schülerpartizipation - Partizipationsmaße und Sinnstrukturen der Partizipation im Vergleich. In: Helsper W, Krüger HH, Fritzsche S, et al., eds. Unpolitische Jugend? Eine Studie zum Verhältnis von Schule, Anerkennung und Politik. Wiesbaden: Verlag für Sozialwissenschaften; 2006: 319-340

Politische Partizipation von Jugendlichen. Der Einfluss von Gleichaltrigen, Familie und Schule auf die politische Teilhabe Heranwachsender

Böhm-Kasper O. Politische Partizipation von Jugendlichen. Der Einfluss von Gleichaltrigen, Familie und Schule auf die politische Teilhabe Heranwachsender. In: Helsper W, Krüger HH, Fritzsche S, et al., eds. Unpolitische Jugend? Eine Studie zum Verhältnis von Schule, Anerkennung und Politik. Wiesbaden: Verlag für Sozialwissenschaften; 2006: 53-74

Weder rechts noch politisch interressiert? Eine Betrachtung politischer und rechter Einstellungen von Jugendlichen in Sachsen-Anhalt und Nordrhein-Westfalen

Krappidel A, Böhm-Kasper O. Weder rechts noch politisch interressiert? Eine Betrachtung politischer und rechter Einstellungen von Jugendlichen in Sachsen-Anhalt und Nordrhein-Westfalen. In: Helsper W, Krüger HH, Fritzsche S, et al., eds. Unpolitische Jugend? Eine Studie zum Verhältnis von Schule, Anerkennung und Politik. Wiesbaden: Verlag für Sozialwissenschaften; 2006: 33-52

Glacial history affected phenotypic differentiation in the Alpine plant Campanula thyrsoides

Numerous widespread Alpine plant species show molecular differentiation among populations from distinct regions. This has been explained as the result of genetic drift during glacial survival in isolated refugia along the border of the European Alps. Since genetic drift may affect molecular markers and phenotypic traits alike, we asked whether phenotypic differentiation mirrors molecular patterns among Alpine plant populations from different regions. Phenotypic traits can be under selection, so we additionally investigated whether part of the phenotypic differentiation can be explained by past selection and/or current adaptation. Using the monocarpic Campanula thyrsoides as our study species, a common garden experiment with plants from 21 populations from four phylogeographic groups located in regions across the Alps and the Jura Mountains was performed to test for differentiation in morphological and phenological traits. Past selection was investigated by comparing phenotypic differentiation among and within regions with molecular differentiation among and within regions. The common garden results indicated regional differentiation among populations for all investigated phenotypic traits, particularly in phenology. Delayed flowering in plants from the South-eastern Alps suggested adaptation to long sub-mediterranean summers and contrasted with earlier flowering of plants experiencing shorter growing seasons in regions with higher elevation to the West. Comparisons between molecular and phenotypic differentiation revealed diversifying selection among regions in height and biomass, which is consistent with adaptation to environmental conditions in glacial refugia. Within regions, past selection acted against strong diversification for most phenotypic traits, causing restricted postglacial adaptation. Evidence consistent with post-glacial adaptation was also given by negative correlation coefficients between several phenotypic traits and elevation of the population's origin. In conclusion, our study suggests that, irrespective of adaptation of plants to their current environment, glacial history can have a strong and long-lasting influence on the phenotypic evolution of Alpine plants

Uppföljning av kvalitetsförändringar i ängs- och betesmark via NILS år 2008

Detta uppdrag är ett led i arbetet med att få fram tillförlitliga data om tillstånd och förändringar i kvalitet och hävd hos ängs- och betesmarker i det svenska odlingslandskapet. Ett av de kvantitativa delmålen för det nationella miljökvalitetsmålet ”Ett rikt odlingslandskap” lyder: ”Senast år 2010 ska samtliga ängs- och betesmarker bevaras och skötas på ett sätt som bevarar deras värden. Arealen hävdad ängsmark ska utökas med minst 5 000 hektar, och arealen hävdad betesmark av de mest hotade typerna ska utökas med minst 13 000 hektar till år 2010” (Miljödepartementet 2001). Detta projekt fokuserar således på naturvärdena, men kan också fungera som ett komplement till miljöstödsstatistiken vad gäller arealer av olika ängs- och betesmarkstyper.Som ett underlag används resultat från Ängs- och betesmarksinventeringen (Ä&B; Jordbruksverket 2005a, b) som genomfördes av Jordbruksverket i samarbete med länsstyrelserna under perioden 2002-2004 och har resulterat i en databas med avgränsning och beskrivning för huvuddelen av Sveriges skyddsvärda slåtter- och betesmarker, den så kallade TUVA-databasen

Differentiation in morphology and flowering phenology between two Campanula thyrsoides L. subspecies

Subspecies are usually characterized by sets of morphological discontinuities. By means of common garden experiments, we investigated genetic differentiation in morphological and phenological traits in two geographically disjunct subspecies of Campanula thyrsoides L., i.e. subsp. thyrsoides (= C.* thyrsoides) occurring in the European Alps and Jura Mountains, and subsp. carniolica (= C.* carniolica) occurring in the Southeastern Alps and the Dinaric Arc. Nine out of 16 investigated traits were significantly different between C.* thyrsoides and C.* carniolica. For C.* carniolica inflorescence length was 1.4×, and above-ground biomass 2.7× higher, while flower density was significantly lower. Campanula* carniolica also showed delayed flowering and flower development from bottom to top compared to C.* thyrsoides which flowered from top to bottom. The inflorescence growth was indeterminate and flowering took several weeks in C.* carniolica, whereas C.* thyrsoides showed determinate flowering, rapidly opening all flowers within a few days. This differentiation in flowering phenology is likely to be adaptive. The submediterranean climate favours indeterminate flowering in C.* carniolica, allowing ongoing growth of the inflorescence throughout the long summer until environmental conditions worsen, whereas determinate and early flowering in C.* thyrsoides is favourable in the short growing season in the high Alps where seed production must be secured before temperature drops. Glacial survival in refugia with different climates (alpine vs. submediterranean) may have caused this regional differentiation