Genetic differentiation and admixture between sibling allopolyploids in the Dactylorhiza majalis complex

Allopolyploidization often happens recurrently, but the evolutionary significance of its iterative nature is not yet fully understood. Of particular interest are the gene flow dynamics and the mechanisms that allow young sibling polyploids to remain distinct while sharing the same ploidy, heritage and overlapping distribution areas. By using eight highly variable nuclear microsatellites, newly reported here, we investigate the patterns of divergence and gene flow between 386 polyploid and 42 diploid individuals, representing the sibling allopolyploids Dactylorhiza majalis s.s. and D. traunsteineri s.l. and their parents at localities across Europe. We make use in our inference of the distinct distribution ranges of the polyploids, including areas in which they are sympatric (that is, the Alps) or allopatric (for example, Pyrenees with D. majalis only and Britain with D. traunsteineri only). Our results show a phylogeographic signal, but no clear genetic differentiation between the allopolyploids, despite the visible phenotypic divergence between them. The results indicate that gene flow between sibling Dactylorhiza allopolyploids is frequent in sympatry, with potential implications for the genetic patterns across their entire distribution range. Limited interploidal introgression is also evidenced, in particular between D. incarnata and D. traunsteineri. Altogether the allopolyploid genomes appear to be porous for introgression from related diploids and polyploids. We conclude that the observed phenotypic divergence between D. majalis and D. traunsteineri is maintained by strong divergent selection on specific genomic areas with strong penetrance, but which are short enough to remain undetected by genotyping dispersed neutral markers.UE FWF; P22260UE: Y66

Groundwater in a water-rich environment : Wales, a land of plenty

Traditionally, Wales has relied on surface water, with only 8% of the total public supply currently derived from groundwater sources. There are various significant aquifers in Wales, including the Carboniferous Limestone in South and North-East Wales and the Triassic aquifer in the Vale of Clwyd, as well as superficial granular deposits that are of particular importance in West Wales. Groundwater quality is generally good and minimal treatment is required. Hydrogeological data in the public domain for Wales are scarce: the Carboniferous Limestone, for example, is particularly poorly documented. Despite this lack of information there are some notable groundwater schemes, but current legislative aspects now require a better overall understanding of the hydrogeology of Wales. A key recommendation is the preparation of public domain data-sets and a comprehensive report on the hydrogeology of Wales

Microperimetric changes in neovascular age-related macular degeneration treated with ranibizumab

PURPOSE: To assess the value of microperimetry in eyes with neovascular age-related macular degeneration previously treated with ranibizumab and now in the maintenance phase of therapy.METHODS: A total of 21 eyes (14 patients) were included. Microperimetry was performed using the Macular Integrity Assessment Device on at least three occasions for each eye. Intravitreal ranibizumab was administered if visual acuity (VA) or optical coherence tomography (OCT) showed signs of active disease.RESULTS: Five eyes showed no change in VA or OCT findings, and required no intravitreal injections. In these eyes, mean threshold sensitivity (TS) decreased by 13% (paired t-test, P=0.05) during the study period, but fixation stability (FS) was unchanged. In all, 16 eyes showed signs of disease activity, and therefore required ranibizumab injections during the study. In these eyes, VA, central retinal thickness (CRT), FS, and TS remained unchanged during follow-up. Peak TS was noted when CRT was 210 ?m; above or below 210 ?m, there was a gradual reduction in TS.CONCLUSION: This study has provided novel information on the relationship between macular sensitivity, CRT, and VA in the maintenance phase of ranibizumab therapy. Patients with stable VA and CRT may still have deteriorating retinal sensitivity. This is usually a late manifestation and may indicate subclinical CNV activity.<br/

Functionally associated molecular genetic marker map construction in perennial ryegrass (Lolium perenne L.)

A molecular marker-based map of perennial ryegrass (Lolium perenne L.) has been constructed through the use of polymorphisms associated with expressed sequence tags (ESTs). A pair-cross between genotypes from a North African ecotype and the cultivar Aurora was used to generate a two-way pseudo-testcross population. A selection of 157 cDNAs assigned to eight different functional categories associated with agronomically important biological processes was used to detect polymorphic EST-RFLP loci in the F 1(NA 6 x AU 6) population. A comprehensive set of EST-SSR markers was developed from the analysis of 14,767 unigenes, with 310 primer pairs showing efficient amplification and detecting 113 polymorphic loci. Two parental genetic maps were produced: the NA 6 genetic map contains 88 EST-RFLP and 71 EST-SSR loci with a total map length of 963 cM, while the AU 6 genetic map contains 67 EST-RFLP and 58 EST-SSR loci with a total map length of 757 cM. Bridging loci permitted the alignment of homologous chromosomes between the parental maps, and a sub-set of genomic DNA-derived SSRs was used to relate linkage groups to the perennial ryegrass reference map. Regions of segregation distortion were identified, in some instances in common with other perennial ryegrass maps. The EST-derived marker-based map provides the basis for in silico comparative genetic mapping, as well as the evaluation of co-location between QTLs and functionally associated genetic loci