The genus Arabidopsis provides a unique opportunity to study fundamental biological questions in plant sciences utilizing the diploid model species A. thaliana and A. lyrata. However, only a few studies have focused on introgression and hybrid speciation in Arabidopsis, although polyploidy is a common phenomenon within this genus. More recently, there is growing evidence of significant gene flow between the various Arabidopsis species. So far, we know A. suecica and A. kamchatica as fully stabilized allopolyploid species. Both species evolved during Pleistocene glaciation and deglaciation cycles in Fennoscandinavia and the amphi-Beringian region, respectively. These hybrid studies were conducted either on a phylogeographic scale, or hybridization was reconstructed experimentally in the laboratory. With our study we focus at a regional and populational level. Our research area is located in the foothills of the Eastern Austrian Alps, where two Arabidopsis species, A. arenosa and A. lyrata ssp. petraea, are sympatrically distributed. Our hypothesis of genetic introgression, migration, and adaptation to the changing environment during the Pleistocene has been confirmed: We observed significant, mainly unidirectional gene flow between the two species, which has given rise to the tetraploid A. lyrata. This cytotype was able to escape from the narrow ecological niche occupied by diploid A. lyrata ssp. petraea on limestone outcrops by migrating northward into siliceous areas, leaving behind a trail of genetic differentiation.
Microsatellite raw data (seven markers) of di- and tetraploid Arabidopsis arenosa and A. lyrata ssp. petraea from Eastern Austria and the Western Carpathians
Data are deposited as BAPS input file. Individuals are listed in the first column. Their unique identification numbers comprise a population number first and an individual number second. In rare cases a third number is found between these two, which further characterizes the population and refers to our internal unique identifier system. POP stands for "population". Taxonomic assignment of the populations is as follows: diploid Arabidopsis arenosa (126-915141), tetraploid A. arenosa (03-81), diploid A. lyrata ssp. petraea (115-74), tetraploid A. lyrata ssp. petraea (01-140). In columns two-eight the microsatellite markers are listed (ATTS0392, SLL2, ICE13, ICE7, NGA162, ICE14, AthZFPG). Each allele of each marker was annotated with a two digit code number.
TableS4.xls
Morphometric raw data (29 characters) of di- and tetraploid Arabidopsis arenosa and A. lyrata ssp. petraea from Eastern Austria and the Western Carpathians
In the first column the individuals are listed. Their unique identification numbers comprise a population number first and an individual number second. In rare cases a third number is found between these two, which further characterizes the population and refers to our internal unique identifier system. Taxonomic assignment of the populations is as follows: diploid Arabidopsis arenosa (915140-915141), tetraploid A. arenosa (Ex04-93), diploid A. lyrata ssp. petraea (87-74), tetraploid A. lyrata ssp. petraea (01-95). In columns 2-24 morphological characters are listed. The character abbreviations 1-29 are as follows: Number of upper stem leaves above the midpoint of the stem (1), plant height (2), number of flowers (3), number of stem leaves (4), length of leafy stem part (5), length of second stem leaf (6), width of second stem leaf (7), length of uppermost stem leaf (8), width of uppermost stem leaf (9), length of biggest rosette leaf (10), length of biggest rosette leaf from the first leaf tooth to the leaf tip (11), basic number of leaf teeth of the biggest rosette leaf (12), length of stem from the ground rosette to the biggest stem leaf (13), length of stem from the ground rosette to the smallest stem leaf (14), hairs on leafy stem part (15), hairs on stem from the ground rosette to the first leaf (16), simple hairs on stem from the ground rosette to the first leaf (17), bifurcated hairs on stem from the ground rosette to the first leaf (18), trifurcated hairs on stem from the ground rosette to the first leaf (19), hairs on leafless stem part (20), simple hairs on flower buds (21), bifurcated hairs on flower buds (22), trifurcated hairs on flower buds (23), simple hairs on second stem leaf (24), bifurcated hairs on second stem leaf (25), trifurcated hairs on second stem leaf (26), white petal colour (27), light pink petal colour (28), dark pink petal colour (29). Eleven characters are used as ratios, e.g., 2:5. Characters 1-14 are either discrete or continuous quantitative characters. Characters 15-29 are qualitative characters.
TableS6.xls