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Freshwater aquatic plants have increased extinction risks due to strong human pressure and the patchy nature of their habitats. However, their unclear population structure frequently hinders conservation planning. To investigate population subdivision and risks to long-term survival of such species, we combined genetic, morphometric and biogeographical approaches to the example of the endangered water chestnut Trapa natans (Lythraceae) from the southern Alpine lake area (Insubria). Amplified fragment length polymorphism (AFLP) of seven extant local stands revealed similar and intermediate levels of genetic diversity, of which c. 97% was partitioned within lakes. Thus, no signs of strong genetic drift and associated loss of genetic diversity were found, despite a reduction of c. 52% of local populations since the early 19th century. Nuclear ribosomal sequences (ITS1-5.8S rRNA-ITS2) combined with a morphometric study of nuts (based on fresh and historical museum material) revealed the presence of two genetically and morphologically slightly distinct lineages, one of which went extinct during the 20th century after a prolonged period of hyper-eutrophication. Taken together, our results indicate the current presence of one large Insubric Trapa population. To prevent genetic risks to survival associated with small population size and increasing fragmentation due to past extinctions, freshwater managers should preserve the large census sizes still present in many Insubric lakes and reduce eutrophication.

Gene drives are genetic elements in sexually reproducing organisms that skew the pattern of inheritance of a given characteristic. They can be used to spread a characteristic that can alter or even reduce the numbers of individuals in wild populations of a certain species. As they spread by being inherited from one generation to the next, they could persist in populations long-term. The spreading property of gene drives could be a source of great potential in areas as diverse as the control of disease vectors, invasive species, agricultural pests and predators of endangered species. However, the same property may make containment challenging and therefore may also pose novel envi- ronmental risks. The evaluation, distribution of risks and benefits and the fact that gene drives may be seen as a particularly profound interference with nature further raises novel ethical considerations.

Despite the remarkable species richness of the Mediterranean flora and its well-known geological history, few studies have investigated its temporal and spatial origins. Most importantly, the relative contribution of geological processes and long-distance dispersal to the composition of contemporary Mediterranean biotas remains largely unknown. We used phylogenetic analyses of sequences from six chloroplast DNA markers, Bayesian dating methods, and ancestral area reconstructions, in combination with paleogeographic, paleoclimatic, and ecological evidence, to elucidate the time frame and biogeographic events associated with the diversification of Araceae in the Mediterranean Basin. We focused on the origin of four species, Ambrosina bassii, Biarum dispar, Helicodiceros muscivorus, Arum pictum, subendemic or endemic to Corsica, Sardinia, and the Balearic Archipelago. The results support two main invasions of the Mediterranean Basin by the Araceae, one from an area connecting North America and Eurasia in the Late Cretaceous and one from the Anatolian microplate in western Asia during the Late Eocene, thus confirming the proposed heterogeneous origins of the Mediterranean flora. The subendemic Ambrosina bassii and Biarum dispar likely diverged sympatrically from their widespread Mediterranean sister clades in the Early-Middle Eocene and Early-Middle Miocene, respectively. Combined evidence corroborates a relictual origin for the endemic Helicodiceros muscivorus and Arum pictum, the former apparently representing the first documented case of vicariance driven by the initial splitting of the Hercynian belt in the Early Oligocene. A recurrent theme emerging from our analyses is that land connections and interruptions, caused by repeated cycles of marine transgressions-regressions between the Tethys and Paratethys, favored geodispersalist expansion of biotic ranges from western Asia into the western Mediterranean Basin and subsequent allopatric speciation at different point

Freshwater aquatic plants have increased extinction risks due to strong human pressure and the patchy nature of their habitats. However, their unclear population structure frequently hinders conservation planning. To investigate population subdivision and risks to long-term survival of such species, we combined genetic, morphometric and biogeographical approaches to the example of the endangered water chestnut Trapa natans (Lythraceae) from the southern Alpine lake area (Insubria). Amplified fragment length polymorphism (AFLP) of seven extant local stands revealed similar and intermediate levels of genetic diversity, of which c. 97% was partitioned within lakes. Thus, no signs of strong genetic drift and associated loss of genetic diversity were found, despite a reduction of c. 52% of local populations since the early 19th century. Nuclear ribosomal sequences (ITS1–5.8S rRNA–ITS2) combined with a morphometric study of nuts (based on fresh and historical museum material) revealed the presence of two genetically and morphologically slightly distinct lineages, one of which went extinct during the 20th century after a prolonged period of hyper-eutrophication. Taken together, our results indicate the current presence of one large Insubric Trapa population. To prevent genetic risks to survival associated with small population size and increasing fragmentation due to past extinctions, freshwater managers should preserve the large census sizes still present in many Insubric lakes and reduce eutrophication.

Genetic and ecological aspects of gene flow from wheat (Triticum aestivum L.) to Aegilops L. species Hybridisation and introgression from crops to wild relatives is a key issue in risk assessment. In the present study, hybridisation and introgression dynamics from hexaploid wheat (2n=42) to tetraploid Aegilops species (2n=28) were investigated by experiments in natural conditions or in the greenhouse, and by genetic analyses. In order to study crop-weed hybridisation as a function of distance, a field trial was set up where Ae. cylindrica was planted in plots at 0, 1, 5, 10 and 25m from a wheat field. In the progeny (14045 seeds sown) we detected hybrids up to 1m from the wheat field. Wheat-specific RAPD fragments were found in Ae. cylindrica x T. aestivum hybrids and BC1 plants. Using a set of Chinese Spring nulli-tetrasomic wheat lines, we were able to assign DNA fragments to wheat chromosomes. Introgressed wheat-specific markers were localised on the three genomes (A, B and D). Some of these markers were transformed into easy-to-use Sequence Characterised Amplified Regions (SCARs), and used to characterise an introgressive series. Ae. cylindrica x GM-wheat hybrids, BC1 and BC1S1 (self-fertilised first backcrosses) were manually produced, in order to study inheritance of transgenes. Female fertility of the hybrids was 0.03-0.6%, BC1 plants had 30-84 chromosomes and displayed highly irregular meioses, their self fertility ranged from 0 to 5.21 %. BC1S1 plants had 28-43 chromosomes and some of them recovered full fertility. One BC1S1 individual contained the bar gene issued from its transgenic wheat progenitor and survived herbicide treatment. A RAPD-based population genetics study was carried out in natural Ae. cylindrica populations, most of them from adventive locations in Switzerland, Italy and the USA. Genetic diversity was low and most of the variance resided among populations. Italian populations from the Aosta valley and a Swiss population were similar or id

Freshwater aquatic plants have increased extinction risks due to strong human pressure and the patchy nature of their habitats. However, their unclear population structure frequently hinders conservation planning. To investigate population subdivision and risks to long-term survival of such species, we combined genetic, morphometric and biogeographical approaches to the example of the endangered water chestnut Trapa natans (Lythraceae) from the southern Alpine lake area (Insubria). Amplified fragment length polymorphism (AFLP) of seven extant local stands revealed similar and intermediate levels of genetic diversity, of which c. 97% was partitioned within lakes. Thus, no signs of strong genetic drift and associated loss of genetic diversity were found, despite a reduction of c. 52% of local populations since the early 19th century. Nuclear ribosomal sequences (ITS1-5.8S rRNA-ITS2) combined with a morphometric study of nuts (based on fresh and historical museum material) revealed the presence of two genetically and morphologically slightly distinct lineages, one of which went extinct during the 20th century after a prolonged period of hyper-eutrophication. Taken together, our results indicate the current presence of one large Insubric Trapa population. To prevent genetic risks to survival associated with small population size and increasing fragmentation due to past extinctions, freshwater managers should preserve the large census sizes still present in many Insubric lakes and reduce eutrophication.

Despite the remarkable species richness of the Mediterranean flora and its well-known geological history, few studies have investigated its temporal and spatial origins. Most importantly, the relative contribution of geological processes and long-distance dispersal to the composition of contemporary Mediterranean biotas remains largely unknown. We used phylogenetic analyses of sequences from six chloroplast DNA markers, Bayesian dating methods, and ancestral area reconstructions, in combination with paleogeographic, paleoclimatic, and ecological evidence, to elucidate the time frame and biogeographic events associated with the diversification of Araceae in the Mediterranean Basin. We focused on the origin of four species, Ambrosina bassii, Biarum dispar, Helicodiceros muscivorus, Arum pictum, subendemic or endemic to Corsica, Sardinia, and the Balearic Archipelago. The results support two main invasions of the Mediterranean Basin by the Araceae, one from an area connecting North America and Eurasia in the Late Cretaceous and one from the Anatolian microplate in western Asia during the Late Eocene, thus confirming the proposed heterogeneous origins of the Mediterranean flora. The subendemic Ambrosina bassii and Biarum dispar likely diverged sympatrically from their widespread Mediterranean sister clades in the Early-Middle Eocene and Early-Middle Miocene, respectively. Combined evidence corroborates a relictual origin for the endemic Helicodiceros muscivorus and Arum pictum, the former apparently representing the first documented case of vicariance driven by the initial splitting of the Hercynian belt in the Early Oligocene. A recurrent theme emerging from our analyses is that land connections and interruptions, caused by repeated cycles of marine transgressions-regressions between the Tethys and Paratethys, favored geodispersalist expansion of biotic ranges from western Asia into the western Mediterranean Basin and subsequent allopatric speciation at different point