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See detailGenetic variability of milk fatty acids.
Arnould, Valérie ULg; Soyeurt, Hélène ULg

in Journal of Applied Genetics (2009), 50(1), 29-39

The milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. The natural sources of variation, such as feeding or genetics, could be used to increase the ... [more ▼]

The milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. The natural sources of variation, such as feeding or genetics, could be used to increase the concentrations of unsaturated fatty acids. The impact of feeding is well described. However, genetic effects on the milk FA composition begin to be extensively studied. This paper summarizes the available information about the genetic variability of FAs. The greatest breed differences in FA composition are observed between Holstein and Jersey milk. Milk fat of the latter breed contains higher concentrations of saturated FAs, especially short-chain FAs. The variation of the delta-9 desaturase activity estimated from specific FA ratios could explain partly these breed differences. The choice of a specific breed seems to be a possibility to improve the nutritional quality of milk fat. Generally, the proportions of FAs in milk are more heritable than the proportions of these same FAs in fat. Heritability estimates range from 0.00 to 0.54. The presence of some single nucleotide polymorphisms could explain partly the observed individual genetic variability. The polymorphisms detected on SCD1 and DGAT1 genes influence the milk FA composition. The SCD1 V allele increases the unsaturation of C16 and C18. The DGAT1 A allele is related to the unsaturation of C18. So, a combination of the molecular and quantitative approaches should be used to develop tools helping farmers in the selection of their animals to improve the nutritional quality of the produced milk fat. [less ▲]

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See detailGenetic variability of test-day stearoyl coenzyme-A desaturase 9 activity
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

in Journal of Dairy Science (2009), 92(E-suppl.1), 353-354

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of ... [more ▼]

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of unsaturated fatty acids. The impact of feeding is well described; however, genetics effects on the milk FA composition are not well studied. Increasing the unsaturated fatty acids contents of bovine milk could have the potential to raise the nutritive and therapeutic values of dairy products. The stearoyl Coenzyme-A desaturase 9 (delta-9) gene was identified as a potential functional candidate gene affecting milk fat composition in dairy cattle. The objective of this research was to study the genetic variability on this enzyme activity across lactations. A total of 199,977 test-day records were obtained from 29,603 Holstein cows in first lactation, 154,267 records from 23,453 Holstein cows in second lactation, and 173,244 records from 75,887 Holstein cows in third and later lactations. The used model was a multiple-trait random regressions test-day model. Fixed effects were: herd × date of test, and class of age. Random effects were: herd × year of calving, permanent environmental, additive genetic, and residual effects. The studied traits were milk yield, protein content, percentage of fat, monounsaturated fatty acids estimated by mid-infrared spectrometry, and the ratios reflecting the delta-9 activity. Obtained heritability estimates of delta-9 as well as the genetic and phenotypic correlations varied across lactations. These results suggest potential improvements of milk fat composition based on delta-9 activity using animal selection and appropriate management practices. [less ▲]

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See detailGenetic variability of test-day stearoyl coenzyme-A desaturase 9 activity
Arnould, Valérie ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

Conference (2009, July)

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of ... [more ▼]

Milk fatty acid (FA) profile is far from the optimal fat composition in regards to human health. Different natural sources of variation such as feeding or genetics could be used to modify the contents of unsaturated fatty acids. The impact of feeding is well described; however, genetics effects on the milk FA composition are not well studied. Increasing the unsaturated fatty acids contents of bovine milk could have the potential to raise the nutritive and therapeutic values of dairy products. The stearoyl Coenzyme-A desaturase 9 (delta-9) gene was identified as a potential functional candidate gene affecting milk fat composition in dairy cattle. The objective of this research was to study the genetic variability on this enzyme activity across lactations. A total of 199,977 test-day records were obtained from 29,603 Holstein cows in first lactation, 154,267 records from 23,453 Holstein cows in second lactation, and 173,244 records from 75,887 Holstein cows in third and later lactations. The used model was a multiple-trait random regressions test-day model. Fixed effects were: herd × date of test, and class of age. Random effects were: herd × year of calving, permanent environmental, additive genetic, and residual effects. The studied traits were milk yield, protein content, percentage of fat, monounsaturated fatty acids estimated by mid-infrared spectrometry, and the ratios reflecting the delta-9 activity. Obtained heritability estimates of delta-9 as well as the genetic and phenotypic correlations varied across lactations. These results suggest potential improvements of milk fat composition based on delta-9 activity using animal selection and appropriate management practices. [less ▲]

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See detailGenetic variability of the mid-infrared prediction of lactoferrin content in milk for Walloon Holstein first-parity cows
Leclercq, Gil ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg et al

in Livestock Science (2013), 151(2-3), 158-162

The objective of this study was to assess the genetic variability of the mid-infrared prediction of lactoferrin content in milk (pLF) in Holstein first-parity cows. Variance components were estimated by ... [more ▼]

The objective of this study was to assess the genetic variability of the mid-infrared prediction of lactoferrin content in milk (pLF) in Holstein first-parity cows. Variance components were estimated by Average Information Restricted Maximum Likelihood using a single-trait test-day random regression animal model. The dataset included 395,287 test-day records from 67,178 cows in 1190 herds from the Walloon Region of Belgium. Average pLF was 164.89. mg/L and the standard deviation was 76.07. mg/L. Frequency distribution for pLF was slightly asymmetrical, and pLF seemed to increase almost linearly all along the first lactation after a sharp decrease in early lactation. Genetic variance of pLF increased with days in milk within lactation while the permanent environmental variance was the highest in early lactation, then decreased to become lower than genetic variance at 50 days in milk, and finally increased in the last lactation stages. The pLF was a moderately heritable trait. Daily heritability of pLF was the lowest at 5 days in milk (0.19), then increased to reach a maximum at 260 days in milk (0.44), and finally decreased for the last stages of lactation (0.35 at 365 days in milk). Results from this study indicated that pLF is variable and heritable over the lactation and therefore it could be changed by genetic selection. © 2012 Elsevier B.V. [less ▲]

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See detailGenetic variability of the Skyros pony breed and its relationship with other Greek and foreign horse breeds
Bömcke, Elisabeth ULg; Gengler, Nicolas ULg; Cothran, E. G.

in Book of Abstracts of the 59th Annual Meeeting of the European Association for Animal Production (EAAP) (2008, August)

On the basis of phenotypes and genotypes, seven native breeds were identified in Greece. The Skyros pony is the more distinctive of these breeds. Using blood group and microsatellite loci, the aim of this ... [more ▼]

On the basis of phenotypes and genotypes, seven native breeds were identified in Greece. The Skyros pony is the more distinctive of these breeds. Using blood group and microsatellite loci, the aim of this study was to assess the genetic diversity of Skyros breed, using also available genealogical information, and to investigate its relationships with the other Greek and foreign horse breeds. Results showed that the Skyros breed presented similar level of genetic diversity to other European breeds. Comparisons between DNA-based and pedigree-based results showed that the loss of genetic diversity has probably occurred before the beginning of breed registration. However, the relatively high levels of heterozygosity and Polymorphism Information Content values indicated still sufficient residual genetic variability that could be useful for planning future breeding strategies for the breed conservation. Relationship study showed no association between genetic variation of native Greek breed and population size or degree of geographic isolation. Compared to other domestic breeds, most of the Greek breed showed closest relationships with Middle Eastern breeds, while the Skyros breed clustered surprisingly with Lithuanian horses. [less ▲]

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See detailGenetic variance in environmental sensitivity for milk and milk quality in Walloon Holstein cattle
Vandenplas, Jérémie ULg; Bastin, Catherine ULg; Gengler, Nicolas ULg et al

in Book of Abstracts of the 63rd Annual Meeting of the European Federation of Animal Science (2012)

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See detailGenetic variance in environmental sensitivity for milk and milk quality in Walloon Holstein cattle
Vandenplas, Jérémie ULg; Bastin, Catherine ULg; Gengler, Nicolas ULg et al

Conference (2012, August 27)

Animals that are robust to environmental changes are desirable in the current dairy industry. This difference in environmental sensitivity can be studied through the heterogeneity of residual variance ... [more ▼]

Animals that are robust to environmental changes are desirable in the current dairy industry. This difference in environmental sensitivity can be studied through the heterogeneity of residual variance while homogeneous residual variance between animals is usually assumed homogeneous in traditional genetic evaluations. The aim of this study was to study genetic heterogeneity of residual variance by the estimation of variance components in residual variance for 5 milk and milk quality traits. 146,027 test-day records from 26,887 Walloon Holstein first-parity cows in 747 herds were available. All cows had at least 3 records and had a known sire. These sires had at least 10 cows with records and each herd x test-day had at least 5 cows. Five traits, milk yield, somatic cell score, and content in milk (g/dL) of oleic acid (C18:1 cis-9), monounsaturated and unsaturated fatty acids, were analyzed separately. Estimation of variance components was performed by running iteratively Expectation Maximization-Restricted Maximum Likelihood algorithm by the implementation of double hierarchical generalized linear models. For all traits, the genetic standard deviation in residual variance (i.e. approximately the genetic coefficient of variation of residual variance) was low and ranged between 0.12 and 0.17. The standard deviations due to herd x test day and permanent environment in residual variance ranged between 0.35 and 0.44 for herd x test-day effect and between 0.55 and 0.96 for permanent environmental effect. This study shows the heterogeneity of residual variance and the existence of some genetic variance in environmental sensitivity for all studied traits in the Walloon Holstein dairy cattle. [less ▲]

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See detailGenetic variance in micro-environmental sensitivity for milk and milk quality in Walloon Holstein cattle
Vandenplas, Jérémie ULg; Bastin, Catherine ULg; Gengler, Nicolas ULg et al

in Journal of Dairy Science (2013), 96

Animals that are robust to environmental changes are desirable in the current dairy industry. Genetic differences in micro-environmental sensitivity can be studied through heterogeneity of residual ... [more ▼]

Animals that are robust to environmental changes are desirable in the current dairy industry. Genetic differences in micro-environmental sensitivity can be studied through heterogeneity of residual variance between animals. However, residual variance between animals is usually assumed homogeneous in traditional genetic evaluations. The aim of this study was to investigate genetic heterogeneity of residual variance by estimating variance components in residual variance for milk yield, somatic cell score, contents in milk (g/dL) of two groups of milk fatty acids (i.e. saturated fatty acids and unsaturated fatty acids) and the content in milk of one individual fatty acid (i.e. the oleic acid, C18:1 cis-9), for first-parity Holstein cows in the Walloon Region of Belgium. A total of 146,027 test-day records from 26,887 cows in 747 herds were available. All cows had at least three records and had a known sire. These sires had at least 10 cows with records and each herd x test-day had at least five cows. The five traits were analyzed separately based on fixed lactation curve and random regression test-day models for the mean. Estimation of variance components was performed by running iteratively Expectation Maximization-Restricted Maximum Likelihood algorithm by the implementation of double hierarchical generalized linear models. Based on fixed lactation curve test-day mean models, heritability for residual variances ranged between 1.01*10-3 and 4.17*10-3 for all traits. The genetic standard deviation in residual variance (i.e. approximately the genetic coefficient of variation of residual variance) ranged between 0.12 and 0.17. Therefore, some genetic variance in micro-environmental sensitivity existed in the Walloon Holstein dairy cattle for the five studied traits. The standard deviations due to herd x test-day and permanent environment in residual variance ranged between 0.36 and 0.45 for herd x test-day effect and between 0.55 and 0.97 for permanent environmental effect. Therefore, non-genetic effects also contributed substantially to the micro-environmental sensitivity. Results also showed that the addition of random regressions to the mean model did not reduce heterogeneity in residual variance and that genetic heterogeneity of residual variance was not simply an effect of an incomplete mean model. [less ▲]

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See detailGenetic variants in REC8, RNF212, and PRDM9 influence male recombination in cattle.
Sandor, Cynthia ULg; Li, Wanbo ULg; Coppieters, Wouter ULg et al

in PLoS Genetics (2012), 8(7), 1002854

We use >250,000 cross-over events identified in >10,000 bovine sperm cells to perform an extensive characterization of meiotic recombination in male cattle. We map Quantitative Trait Loci (QTL ... [more ▼]

We use >250,000 cross-over events identified in >10,000 bovine sperm cells to perform an extensive characterization of meiotic recombination in male cattle. We map Quantitative Trait Loci (QTL) influencing genome-wide recombination rate, genome-wide hotspot usage, and locus-specific recombination rate. We fine-map three QTL and present strong evidence that genetic variants in REC8 and RNF212 influence genome-wide recombination rate, while genetic variants in PRDM9 influence genome-wide hotspot usage. [less ▲]

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See detailGenetic variation among the geographic population of the grain aphid, Sitobion avenae (Hemiptera: Aphididae) in China inferred from mitochondrial COI gene sequence
Xu, Zhao-Huan; Chen, Julian; Cheng, Deng-Fa et al

in Agricultural Sciences in China (2011), 10(7), 1041-1048

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See detailGenetic variation and evolution in the genus Apodemus (Muridae : Rodentia)
Filippucci, M. G.; Macholan, M.; Michaux, Johan ULg

in Biological Journal of the Linnean Society (2002), 75(3), 395-419

Genetic variation was studied using protein electrophoresis of 28-38 gene loci in 1347 specimens of Apodemus agrarius, A. peninsulac, A. flavicollis, A. sylvaticus, A. alpicola, A. uralensis, A. cf ... [more ▼]

Genetic variation was studied using protein electrophoresis of 28-38 gene loci in 1347 specimens of Apodemus agrarius, A. peninsulac, A. flavicollis, A. sylvaticus, A. alpicola, A. uralensis, A. cf. hyrcanicus, A. hermonensis, A. m. mystacinus and A. in. epimelas, representing 121 populations from Europe, the Middle East, and North Africa. Mean values of heterozygosity per locus for each species ranged from 0.02 to 0.04. Mean values of Nei's genetic distance (D) between the taxa ranged from 0.06 (between A. flavicollis and A. alpicola) to 1.34 (between A. uralensis and A. agrarius). The highest values of D were found between A. agrarius and other Apodemus species (0.62-1.34). These values correspond to those generally observed between genera in small mammals. Our data show that A. agrarius and A. peninsulae are sister species, well-differentiated from other taxa. High genetic distance between A. m. mystacinus and A. m. epimelas leads us to consider them distinct species and sister taxa to other Western Palaearctic species of the subgenus Sylvaemus. The data also suggest a recent separation of members of the latter group from a common ancestor, and subsequent rapid radiation, making it difficult to infer phylogenetic relationships. Some taxonomic implications of the results are discussed further. (C) 2002 The Linnean Society of London. [less ▲]

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See detailGenetic variation in heat stress tolerance of Holsteins producing under a continental temperate environment
Hammami, Hedi ULg; Arnould, Valérie ULg; Bormann, Jeanne et al

Poster (2012)

Under projected climate changes, considerations for heat stress tolerance but also for genotype by environment interactions should enter breeding decisions, both for importing, but also exporting ... [more ▼]

Under projected climate changes, considerations for heat stress tolerance but also for genotype by environment interactions should enter breeding decisions, both for importing, but also exporting countries. Most studies concerning the breeding strategies on heat stress tolerance used the temperature humidity index (THI) to assess the thermal stress in a given environment and assumed a specific threshold to each studied population with the same response to each individual above this threshold. Recently new comprehensive thermal indices (TI) integrating radiation solar, wind speed, in addition to temperature and relative humidity were developed. Therefore, the aim of this study is advanced modelling of milk yield trait to evaluate the genetic variation in heat stress tolerance of Holsteins in a temperate environment using random regressions models and six new comprehensive TI. A total of 107,350 test day milk records were available for 12,099 primiparous Holsteins calving from 2000 to 2010. Test-day milk records were merged with meteorological data from 14 public weather stations across Luxembourg. Daily values of 6 new comprehensive TI (3 THI and 3 apparent temperature indices) were calculated by averaging hourly TI over 24 hours. The average distance between herds and their meteorological reference station was of 16 km. Sensitivity of cows to the climate environmental conditions was modelled by applying a reaction norm for each animal, representing its EBV for milk yield on values of the TI on the day in milk (DIM). Six separate random regression models were applied using time-dependent (DIM) and specific TI-dependent covariates. Random effects were additive genetic, permanent environmental, and herd year modelled with Legendre polynomials of order 2 for both DIM and TI. Genetic variances of the different TI evaluated in this study represent 27 to 30% of their correspondent variances for DIM effect. Permanent environmental and genetic variances of TI effect were in the same range. Additive genetic variances and heritabilities for daily milk yield slightly decreased with increasing degrees of the different THI and apparent temperature indices. The average daily milk heritability overall the lactation at the mean of each of the six TI was of 0.28. Genetic correlations between adjacent points across the lactation were > 0.90. Correlations between extreme distant DIM (e.g. early and late lactation stage) were reduced at 0.38 to 0.52. The overall genetic correlations between the different values of each TI remain high (> 0.85). EBV’s summing regular additive effect (DIM effect) and tolerance to heat stress (TI effect) were computed for several combinations of DIM and TI values. Ranking for sires and cows did not change among the 6 heat stress indicators. The correlations between EBVs estimated with the six models were greater than 0.90. In conclusion, the different models depicted genetic variation of milk yield among combinations of DIM and TI levels without defining thresholds in advance. Genetic variation was slightly lower when TI values exceed the thermoneutral zone. Breeding for reduced thermal sensitivity using any of the six indicators of heat stress evaluated in this study is possible. The indicator TI2 representing the adjusted THI for radiation solar and wind speed is favoured because it was the indicator that did identify the highest yearly milk losses under this continental temperate environment. [less ▲]

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See detailGenetic variation in PLAG1 associates with early life body weight and peripubertal weight and growth in Bos taurus.
Littlejohn, M.; Grala, T.; Sanders, K. et al

in Animal Genetics (2012), 43(5), 591-4

Variation at the pleiomorphic adenoma gene 1 (PLAG1) locus has recently been implicated in the regulation of stature and weight in Bos taurus. Using a population of 942 outbred Holstein-Friesian dairy ... [more ▼]

Variation at the pleiomorphic adenoma gene 1 (PLAG1) locus has recently been implicated in the regulation of stature and weight in Bos taurus. Using a population of 942 outbred Holstein-Friesian dairy calves, we report confirmation of this effect, demonstrating strong association of early life body weight with PLAG1 genotype. Peripubertal body weight and growth rate were also significantly associated with PLAG1 genotype. Growth rate per kilogram of body weight, daily feed intake, gross feed efficiency and residual feed intake were not significantly associated with PLAG1 genotype. This study supports the status of PLAG1 as a key regulator of mammalian growth. Further, the data indicate the utility of PLAG1 polymorphisms for the selection of animals to achieve enhanced weight gain or conversely to aid the selection of animals with lower mature body weight and thus lower maintenance energy requirements. [less ▲]

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See detailGenetic variation in the autophagy gene ULK1 and risk of Crohn's disease
Henckaerts, Liesbeth; Cleynen, Isabelle; Brinar, Marko et al

in Inflammatory Bowel Diseases (2011), 17(6), 1392-1397

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See detailGenetic variation in the familial Mediterranean fever gene (MEFV) and risk for Crohn's disease and ulcerative colitis.
Villani, Alexandra-Chloé; Lemire, Mathieu; Louis, Edouard ULg et al

in PLoS ONE (2009), 4(9), 7154

BACKGROUND AND AIMS: The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1beta processing. Pyrin has ... [more ▼]

BACKGROUND AND AIMS: The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1beta processing. Pyrin has been shown to interact with the gene product of NLRP3, NALP3/cryopyrin, also an important active member of the inflammasome. The NLRP3 region was recently reported to be associated with Crohn's disease (CD) susceptibility. We therefore sought to evaluate MEFV as an inflammatory bowel disease (IBD) susceptibility gene. METHODOLOGY AND RESULTS: MEFV colonic mucosal gene expression was significantly increased in experimental colitis mice models (TNBS p<0.0003; DSS p<0.006), in biopsies from CD (p<0.02) and severe ulcerative colitis (UC) patients (p<0.008). Comprehensive genetic screening of the MEFV region in the Belgian exploratory sample set (440 CD trios, 137 UC trios, 239 CD cases, 96 UC cases, and 107 healthy controls) identified SNPs located in the MEFV 5' haplotype block that were significantly associated with UC (rs224217; p = 0.003; A allele frequency: 56% cases, 45% controls), while no CD associations were observed. Sequencing and subsequent genotyping of variants located in this associated haplotype block identified three synonymous variants (D102D/rs224225, G138G/rs224224, A165A/rs224223) and one non-synonymous variant (R202Q/rs224222) located in MEFV exon 2 that were significantly associated with UC (rs224222: p = 0.0005; A allele frequency: 32% in cases, 23% in controls). No consistent associations were observed in additional Canadian (256 CD trios, 91 UC trios) and Scottish (495 UC, 370 controls) sample sets. We note that rs224222 showed marginal association (p = 0.012; G allele frequency: 82% in cases, 70% in controls) in the Canadian sample, but with a different risk allele. None of the NLRP3 common variants were associated with UC in the Belgian-Canadian UC samples and no significant interactions were observed between NLRP3 and MEFV that could explain the observed flip-flop of the rs224222 risk allele. CONCLUSION: The differences in association levels observed between the sample sets may be a consequence of distinct founder effects or of the relative small sample size of the cohorts evaluated in this study. However, the results suggest that common variants in the MEFV region do not contribute to CD and UC susceptibility. [less ▲]

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See detailGenetic variation of the bovine thyroglobulin gene studied at the DNA level.
Georges, Michel ULg; Lequarré, Anne-Sophie ULg; Hanset, R. et al

in Animal Genetics (1987), 18(1), 41-50

The bovine thyroglobulin gene has been analysed for variation using restriction endonucleases. Six independent restriction fragment length polymorphisms have been identified. One of these results most ... [more ▼]

The bovine thyroglobulin gene has been analysed for variation using restriction endonucleases. Six independent restriction fragment length polymorphisms have been identified. One of these results most probably from a 2.5-kb deletion, the others being compatible with point mutations. We determined that an individual taken at random within the Belgian White and Blue breed is, on average, heterozygous for one out of 1700 nucleotides within the thyroglobulin gene. [less ▲]

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See detailGenetic variation of Viola calaminaria, an endemic metallophyte
Bizoux, Jean-Philippe ULg; Mahy, Grégory ULg

in Proceedings of the GfÖ: Lanscapes, ecosystems and populations: dynamics, functions and conservation (2005)

The zinc violet, Viola calaminaria (DC) Lej., is a rare threatened species in Belgium which is endemic to metalliferous sites. Yours aims were to assess the genetic structure of the species at the scale ... [more ▼]

The zinc violet, Viola calaminaria (DC) Lej., is a rare threatened species in Belgium which is endemic to metalliferous sites. Yours aims were to assess the genetic structure of the species at the scale of its distribution range, including differentiation with related taxa Viola guesphalica and to examine the influence of population size and recent colonisation events on population genetic structure in order to identify conservation priorities. The analysis of genetic variation (Amova) showed a strong population differentiation (Fst = 0.26) with a regional group differentiation. The V. guestfalica population exhibits the larger differentiation (Fst = 0.19). The levels of population genetic diversity (Hs) varied from 0.21 to 0.29. Mean genetic differentiation among ancient populations (Fst =0.26) is higher than genetic differentiation among recent populations (Fst =0.18) while any difference appears on genetic diversity. This strong population differentiation suggests a low gene flow between populations but sufficient within population to maintain high level of diversity. For management, the result implies a hierarchical conservation strategy including small population. New populations had as much genetically importance than old populations. No foundation effects were detected in the recent populations. These populations probably result from multiple colonization effects from more than one source population. Finally, even if some V. calaminaria populations exhibit a similar level of genetic differentiation of V. guestfalica population, this one appeared as a particular genetic pool. [less ▲]

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See detailGenetic variation within β3 subunit integrin sequences and rodent species susceptibility to pathogenic hantaviruses
Pagès, Marie ULg; Tatard, Caroline; Galan, Maxime et al

Conference (2010, April)

Recent investigations in rodent systematics and epidemiology have led to the discovery of numerous Hantavirus species in Asia. As seroprevalences are very low, the screening of thousands of rodents is ... [more ▼]

Recent investigations in rodent systematics and epidemiology have led to the discovery of numerous Hantavirus species in Asia. As seroprevalences are very low, the screening of thousands of rodents is required to genetically identify these hantaviruses and to determine their human pathogenesis as well as their rodent reservoirs. Pathogenic and non-pathogenic hantaviruses use different integrin receptors to enter cells. In particular, human integrins αIIaβ3 and αvβ3 can mediate cellular entry of hemorragic fever with renal syndrome (HFRS)- and hemorragic pulmonary syndrome (HPS)-causing hantaviruses. In contrast, non-pathogenic or low pathogenic hantaviruses were demonstrated to enter the cell via integrin αvβ1. We tested the hypothesis that amino-acid variation in β3 subunit integrin sequences could provide keys to determine a priori the possibility for a rodent species to carry a human pathogenic hantavirus. We sequenced 330 bp of the β3 chain integrin encompassing the Plexin-Semaphorin-Integrin domain, for 63 individuals corresponding to 14 Asian rodent species. We found 65 variable sites and a high level of divergence between species (up to 12%). Although the genetic variation reflected the neutral phylogeny of these species, we found one site differing between rodent species carrying pathogenic hantaviruses and non reservoir rodent species. We also detected another variable site that could be under positive selection, but only in rodent species that do not carry pathogenic hantaviruses. This site did not exhibit any genetic variation in rodent species that carry hantaviruses. In consequence, it is likely that knowing the amino-acid present at this position for a given rodent species could help us determining a priori whether this species is a reservoir of pathogenic hantaviruses. Further investigations are required to examine whether amino-acid changes at these residues could mediate conformational changes that would prevent the fixation of pathogenic hantaviruses. [less ▲]

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See detailGenetic variations in toll-like receptor pathway and lung function decline in Cystic fibrosis patients.
Haerynck, F.; Mahachie John, Jestinah ULg; Van Steen, Kristel ULg et al

in Human immunology (2013), 74(12), 1649-55

The toll-like receptor (TLR) family maintains pulmonary homeostasis by pathogen recognition, clearance and regulation of inflammation. Genes affecting inflammation response play a key role in modifying ... [more ▼]

The toll-like receptor (TLR) family maintains pulmonary homeostasis by pathogen recognition, clearance and regulation of inflammation. Genes affecting inflammation response play a key role in modifying Cystic fibrosis (CF) lung disease severity. We assessed the impact of single nucleotide polymorphisms (SNPs) of TLR genes (TLR1 to TLR10, CD14, lipopolyssacharide-binding protein (LBP)) on lung function in CF patients. Each SNP was tested for time-dependent effect on FEV1, using six genetic models. In addition, we investigated associations between SNP genotypes and extreme subject specific slopes of FEV1 decline. Variant alleles of polymorphisms of TLR2 rs1898830, rs5743708, and rs3804100 demonstrated a consistent association with lung disease severity (p = 0.008, p = 0.006 and p = 0.029 respectively). Patients homozygous for variant C allele of TLR5 polymorphism rs5744174 are more frequently associated with extreme fast FEV1 decline (OR: 20 (95% Confidence Interval:1.85-216.18)). Patients homozygous AA for TLR1 polymorphism rs5743551 are more frequently associated with faster decline of FEV1 compared to heterozygous genotype (OR:7.33 (95% CI:1.63-33.11). Our findings indicate that variations in TLR1, TLR2 and TLR5 genes may influence CF lung function decline. Further functional analysis is required to provide new insights into the pathogenesis of TLRs in CF lung disease severity. [less ▲]

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