Twenty-two highly variable SSR markers were developed in Douglas-fir Pseudotsuga menziesii (Mirb.) Franco from five SSR-enriched genomic libraries. Fifteen PCR primer pairs amplified a single ...codominant locus, while seven primer pairs occasionally amplified two loci. The Mendelian inheritance of all 22 SSRs was confirmed via segregation analyses in several Douglas-fir families. The mean observed heterozygosity and the mean number of alleles per locus were 0.855 (SE=0.020) and 23 (SE=1.6), respectively. Twenty markers were used in genetic linkage analysis and mapped to ten known linkage groups. Because of their high polymorphism and unambiguous phenotypes, 15 single-locus markers were selected as the most suitable for DNA fingerprinting and parentage analysis. Only three SSRs were sufficient to achieve an average probability of exclusion from paternity of 0.998 in a Douglas-fir seed orchard block consisting of 59 parents.
Genetic variation of 17 populations of Pinus mugo Turra was studied using 10 polymorphic allozyme loci. Polymorphism and gene diversity in these populations were comparable to mean values for ...gymnosperm species, but slightly lower than in pines with large and continuous ranges. We did not find significant interpopulation differentiation (F(ST) = 0.041) or isolation by distance, suggesting that gene flow might be extensive or that the time elapsed since the species range became fragmented has been too short for genetic differentiation to arise via genetic drift. We detected moderate and statistically significant levels of inbreeding (mean F(IS) = 0.252) for all loci in all populations. Although there are many possible explanations for this nonequilibrium population structure, we propose that the main reasons for its ubiquity are the peculiar growth form and reproductive biology of P. mugo, which promote excessive near-neighbor pollinations. Populations in Vitosha Mountain and western Stara Planina had the highest levels of inbreeding and the lowest observed heterozygosities. All populations in these mountains are small and isolated, but none of them is under a special regime of protection. Thus, the conservation status of P. mugo populations in Vitosha Mountain and western Stara Planina may deserve reevaluation. Future gene conservation efforts should focus on obtaining information on the genetic variation of adaptive traits in P. mugo.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
One of the most economically important areas within the Welsh agricultural sector is sheep farming, contributing around £230 million to the UK economy annually. Phenotypic selection over several ...centuries has generated a number of native sheep breeds, which are presumably adapted to the diverse and challenging landscape of Wales. Little is known about the history, genetic diversity and relationships of these breeds with other European breeds. We genotyped 353 individuals from 18 native Welsh sheep breeds using the Illumina OvineSNP50 array and characterised the genetic structure of these breeds. Our genotyping data were then combined with, and compared to, those from a set of 74 worldwide breeds, previously collected during the International Sheep Genome Consortium HapMap project.
Model based clustering of the Welsh and European breeds indicated shared ancestry. This finding was supported by multidimensional scaling analysis (MDS), which revealed separation of the European, African and Asian breeds. As expected, the commercial Texel and Merino breeds appeared to have extensive co-ancestry with most European breeds. Consistently high levels of haplotype sharing were observed between native Welsh and other European breeds. The Welsh breeds did not, however, form a genetically homogeneous group, with pairwise F ST between breeds averaging 0.107 and ranging between 0.020 and 0.201. Four subpopulations were identified within the 18 native breeds, with high homogeneity observed amongst the majority of mountain breeds. Recent effective population sizes estimated from linkage disequilibrium ranged from 88 to 825.
Welsh breeds are highly diverse with low to moderate effective population sizes and form at least four distinct genetic groups. Our data suggest common ancestry between the native Welsh and European breeds. These findings provide the basis for future genome-wide association studies and a first step towards developing genomics assisted breeding strategies in the UK.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Flowering in perennial species is directed via complex signalling pathways that adjust to developmental regulations and environmental cues. Synchronized flowering in certain environments is ...a prerequisite to commercial seed production, and so the elucidation of the genetic architecture of flowering time in
Miscanthus
and switchgrass could aid breeding in these underdeveloped species. In this context, we assessed a mapping population in
Miscanthus
and two ecologically diverse switchgrass mapping populations over 3 years from planting. Multiple flowering time quantitative trait loci (QTL) were identified in both species. Remarkably, the most significant
Miscanthus
and switchgrass QTL proved to be syntenic, located on linkage groups 4 and 2, with logarithm of odds scores of 17.05 and 21.8 respectively. These QTL regions contained three flowering time transcription factors:
Squamosa Promoter‐binding protein‐Like
, MADS‐box
SEPELLATA2
and gibberellin‐responsive bHLH137. The former is emerging as a key component of the age‐related flowering time pathway.
Studies of genetic variation can clarify the role of geography and spatio-temporal variation of climate in shaping demography, particularly in temperate zone tree species with large latitudinal ...ranges. Here, we examined genetic variation in narrowleaf cottonwood, Populus angustifolia, a dominant riparian tree. Using multi-locus surveys of polymorphism in 363 individuals across the species' 1800 km latitudinal range, we found that, first, P. angustifolia has stronger neutral genetic structure than many forest trees (simple sequence repeat (SSR) FST=0.21), with major genetic groups corresponding to large apparent geographical barriers to gene flow. Second, using SSRs and putatively neutral sequenced loci, coalescent simulations indicated that populations diverged before the last glacial maximum (LGM), suggesting the presence of population structure before the LGM. Third, the LGM and subsequent warming appear to have had different influences on each of these distinct populations, with effective population size reduction in the southern extent of the range but major expansion in the north. These results are consistent with the hypothesis that climate and geographic barriers have jointly affected the demographic history of P. angustifolia, and point the importance of both factors as being instrumental in shaping genetic variation and structure in widespread forest trees.
Flowering in perennial species is directed via complex signalling pathways that adjust to developmental regulations and environmental cues. Synchronized flowering in certain environments is a ...prerequisite to commercial seed production, and so the elucidation of the genetic architecture of flowering time in Miscanthus and switchgrass could aid breeding in these underdeveloped species. In this context, we assessed a mapping population in Miscanthus and two ecologically diverse switchgrass mapping populations over 3 years from planting. Multiple flowering time quantitative trait loci (QTL) were identified in both species. Remarkably, the most significant Miscanthus and switchgrass QTL proved to be syntenic, located on linkage groups 4 and 2, with logarithm of odds scores of 17.05 and 21.8 respectively. These QTL regions contained three flowering time transcription factors: Squamosa Promoter‐binding protein‐Like, MADS‐box SEPELLATA2 and gibberellin‐responsive bHLH137. The former is emerging as a key component of the age‐related flowering time pathway.
Genetic factors control flowering in the bioenergy species Miscanthus and switchgrass are poorly understood, yet commercial seed production to upscale sustainable bioenergy requires flowering synchronization. Using populations (of both species) with diverse flowering times, we identified a region that was strikingly conserved, not only between Miscanthus and switchgrass, but also with Sorghum, another bioenergy grass. The region contained DNA sequences encoding genes known to be involved in flowering time control in other species, and appears highly important for flowering time regulation. This provides a potential tool to synchronize flowering in these crops to speed up the breeding of new varieties.
The aim of this study was to rapidly identify the temperament type which greatly influences the extent of the dog socialization in young puppies using the statuette test. For that, a total of 27,7 ...week old puppies from 3 breeds used worldwide as companions - Dachshund, Pekinese and Japanese Chin breeds, 9 puppies from each breed were tested 2 times after placing an odourless dog statuette in an empty and unfamiliar room, for specific behavioural activities - purposefulness / orientation, confidence, curiosity, indifference, fear and aggressive traits, leading to the establishment of the temperament type. The L - sanguine type characterizing a strong and balanced temperament - highly correct orientation, high curiosity, no indifference, no fear, and high confidence and no aggressiveness was encountered in 6 Dachshund, 5 Pekinese and only in 3 Japanese puppies. Two puppies from each breed exhibited the second strong temperament, the F - choleric type, differing from the first by a weakly lower orientation and by some aggressive traits. The weak and balanced temperament - low orientation, weak confidence and curiosity but fear signs and no aggressiveness, the G - phlegmatic type was found in only one Dachshund dog but in 4 Pekinese and Japanese Chin dogs whereas the last weak and unbalanced temperament, the A - melancholic or antisocial type was evidenced only in 2 Japanese dogs. These results show that the strong temperament types - L and F at a lesser extend leading to a stable and rapid socialisation can be rapidly and easily determined by the statuette test and were more frequently evidenced in the Dachshund than in Pekinese or Japanese Chin dogs.
There are several theoretical arguments for why the adoption of a common currency (either a currency union or a currency board) may reduce the exchange rate pass‐through (ERPT) to domestic consumer ...prices. This paper examines a broad panel of 101 countries over the period 1976–2006, using two‐stage instrumental‐variable estimation techniques in order to resolve the potential endogeneity problem. The main result is that ERPT indeed tends to decline in countries participating in a common currency arrangement. In particular, there has been a strong reduction in pass‐through in the member countries of the European Monetary Union (EMU) since the launch of the euro. Currency boards do not appear to be different from currency unions – both reduce the pass‐through from depreciation to inflation. Furthermore, the negative impact of common currencies on ERPT is at work in both high‐income and low‐income countries. Finally, most of the reduction in pass‐through to consumer prices under common currency arrangements happens somewhere along the pricing chain between the border and the supermarket shelf.
Previously detected βsp and γ1sp dielectric relaxations on the spectrin-based membrane skeleton (MS) of human red blood cells (RBCs) have been shown sensitive to the attachment of MS to the ...lipid-protein membrane. Such relaxations were now detected on the MS of mammal (rat, horse, bovine, sheep and goat) and "unstrained" chicken RBCs. To become "unstrained" chicken RBCs were subjected consecutively to cold (4°C, >20 h) and either colchicine (15 mM) or vinblastine (30 μM) (4°C, 1 h) that led to irreversible disassembly of their marginal band and an additional portion of their cytoskeleton. With the exception of bovine RBCs, the critical frequency (fc) of either relaxation increased, although at different rates, with the decrease in the volume of RBC species. The strong increase in fc of γ1sp relaxation from 2.5 MHz ("unstrained" chicken RBCs) to 13 MHz (goat RBCs) could indicate denser state of MS in smaller RBC species. The low values of fc of γ1sp relaxation in "unstrained" chicken RBCs (2.5 MHz) and bovine RBCs (4.5 instead of 9 MHz) could be related to their extraordinary thermal stability at the temperature of spectrin denaturation.
Earlier studies have hypothesized that membership in a common currency arrangement (either a currency union or a currency board) is associated with larger current account imbalances (either deficits ...or surpluses) for participating countries. This paper examines a panel of 128 countries over the period 1976–2005, and finds that the current account balances of common currency participants are more highly correlated with fundamental factors (such as net foreign assets, incomes, growth rates, fiscal policy, demographics, resource endowments) than the current accounts of non-participants. Furthermore, this greater sensitivity to fundamentals leads to larger current account imbalances. Participation in a common currency is typically associated with a 1.6 percent increase in a country's current account imbalance. Larger current account imbalances under common currency arrangements could be a sign of increased financial integration. Alternatively, they could reflect the difficulties of current account adjustment under fixed exchange rates.
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