Merete Fredholm
Publications
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4.41Impact points
Identification of a novel idiopathic epilepsy locus in belgian shepherd dogs.
PloS one. 01/2012; 7(3):e33549.
Epilepsy is the most common neurological disorder in dogs, with an incidence ranging from 0.5% to up to 20% in particular breeds. Canine epilepsy can be etiologically defined as idiopathic or symptomatic. Epileptic seizures may be classified as focal with or without secondary generalization, or as p... [more] Epilepsy is the most common neurological disorder in dogs, with an incidence ranging from 0.5% to up to 20% in particular breeds. Canine epilepsy can be etiologically defined as idiopathic or symptomatic. Epileptic seizures may be classified as focal with or without secondary generalization, or as primary generalized. Nine genes have been identified for symptomatic (storage diseases) and one for idiopathic epilepsy in different breeds. However, the genetic background of common canine epilepsies remains unknown. We have studied the clinical and genetic background of epilepsy in Belgian Shepherds. We collected 159 cases and 148 controls and confirmed the presence of epilepsy through epilepsy questionnaires and clinical examinations. The MRI was normal while interictal EEG revealed abnormalities and variable foci in the clinically examined affected dogs. A genome-wide association study using Affymetrix 50K SNP arrays in 40 cases and 44 controls mapped the epilepsy locus on CFA37, which was replicated in an independent cohort (81 cases and 88 controls; combined p = 9.70×10(-10), OR = 3.3). Fine mapping study defined a ∼1 Mb region including 12 genes of which none are known epilepsy genes or encode ion channels. Exonic sequencing was performed for two candidate genes, KLF7 and ADAM23. No variation was found in KLF7 but a highly-associated non-synonymous variant, G1203A (R387H) was present in the ADAM23 gene (p = 3.7×10(-8), OR = 3.9 for homozygosity). Homozygosity for a two-SNP haplotype within the ADAM23 gene conferred the highest risk for epilepsy (p = 6.28×10(-11), OR = 7.4). ADAM23 interacts with known epilepsy proteins LGI1 and LGI2. However, our data suggests that the ADAM23 variant is a polymorphism and we have initiated a targeted re-sequencing study across the locus to identify the causative mutation. It would establish the affected breed as a novel therapeutic model, help to develop a DNA test for breeding purposes and introduce a novel candidate gene for human idiopathic epilepsies.
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1.26Impact points
How the RNA isolation method can affect microRNA microarray results.
Acta biochimica Polonica. 12/2011; 58(4):535-40.
The quality of RNA is crucial in gene expression experiments. RNA degradation interferes in the measurement of gene expression, and in this context, microRNA quantification can lead to an incorrect estimation. In the present study, two different RNA isolation methods were used to perform microRNA mi... [more] The quality of RNA is crucial in gene expression experiments. RNA degradation interferes in the measurement of gene expression, and in this context, microRNA quantification can lead to an incorrect estimation. In the present study, two different RNA isolation methods were used to perform microRNA microarray analysis on porcine brain tissue. One method is a phenol-guanidine isothiocyanate-based procedure that permits isolation of total RNA. The second method, miRVana™ microRNA isolation, is column based and recovers the small RNA fraction alone. We found that microarray analyses give different results that depend on the RNA fraction used, in particular because some microRNAs appear very sensitive to the RNA isolation method. We conclude that precautions need to be taken when comparing microarray studies based on RNA isolated with different methods.
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9.53Impact points
Identification of genomic regions associated with phenotypic variation between dog breeds using selection mapping.
PLoS genetics. 10/2011; 7(10):e1002316.
The extraordinary phenotypic diversity of dog breeds has been sculpted by a unique population history accompanied by selection for novel and desirable traits. Here we perform a comprehensive analysis using multiple test statistics to identify regions under selection in 509 dogs from 46 diverse breed... [more] The extraordinary phenotypic diversity of dog breeds has been sculpted by a unique population history accompanied by selection for novel and desirable traits. Here we perform a comprehensive analysis using multiple test statistics to identify regions under selection in 509 dogs from 46 diverse breeds using a newly developed high-density genotyping array consisting of >170,000 evenly spaced SNPs. We first identify 44 genomic regions exhibiting extreme differentiation across multiple breeds. Genetic variation in these regions correlates with variation in several phenotypic traits that vary between breeds, and we identify novel associations with both morphological and behavioral traits. We next scan the genome for signatures of selective sweeps in single breeds, characterized by long regions of reduced heterozygosity and fixation of extended haplotypes. These scans identify hundreds of regions, including 22 blocks of homozygosity longer than one megabase in certain breeds. Candidate selection loci are strongly enriched for developmental genes. We chose one highly differentiated region, associated with body size and ear morphology, and characterized it using high-throughput sequencing to provide a list of variants that may directly affect these traits. This study provides a catalogue of genomic regions showing extreme reduction in genetic variation or population differentiation in dogs, including many linked to phenotypic variation. The many blocks of reduced haplotype diversity observed across the genome in dog breeds are the result of both selection and genetic drift, but extended blocks of homozygosity on a megabase scale appear to be best explained by selection. Further elucidation of the variants under selection will help to uncover the genetic basis of complex traits and disease.
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2.32Impact points
LUPA: a European initiative taking advantage of the canine genome architecture for unravelling complex disorders in both human and dogs.
Veterinary journal (London, England : 1997). 08/2011; 189(2):155-9.
The domestic dog offers a unique opportunity to explore the genetic basis of disease, morphology and behaviour. Humans share many diseases with our canine companions, making dogs an ideal model organism for comparative disease genetics. Using newly developed resources, genome-wide association studie... [more] The domestic dog offers a unique opportunity to explore the genetic basis of disease, morphology and behaviour. Humans share many diseases with our canine companions, making dogs an ideal model organism for comparative disease genetics. Using newly developed resources, genome-wide association studies in dog breeds are proving to be exceptionally powerful. Towards this aim, veterinarians and geneticists from 12 European countries are collaborating to collect and analyse the DNA from large cohorts of dogs suffering from a range of carefully defined diseases of relevance to human health. This project, named LUPA, has already delivered considerable results. The consortium has collaborated to develop a new high density single nucleotide polymorphism (SNP) array. Mutations for four monogenic diseases have been identified and the information has been utilised to find mutations in human patients. Several complex diseases have been mapped and fine mapping is underway. These findings should ultimately lead to a better understanding of the molecular mechanisms underlying complex diseases in both humans and their best friend.
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Characterisation of five candidate genes within the ETEC F4ab/ac candidate region in pigs.
BMC research notes. 06/2011; 4:225.
ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) that express the F4ab and F4ac fimbriae is a major contributor to diarrhoea outbreaks in the pig breeding industry, infecting both newborn and weaned piglets. Some pigs are resistant to this infection, and susceptibility is inherited as a simple domi... [more] ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) that express the F4ab and F4ac fimbriae is a major contributor to diarrhoea outbreaks in the pig breeding industry, infecting both newborn and weaned piglets. Some pigs are resistant to this infection, and susceptibility is inherited as a simple dominant Mendelian trait. Indentifying the genetics behind this trait will greatly benefit pig welfare as well as the pig breeding industry by providing an opportunity to select against genetically susceptible animals, thereby reducing the number of diarrhoea outbreaks. The trait has recently been mapped by haplotype sharing to a 2.5 Mb region on pig chromosome 13, a region containing 18 annotated genes. The coding regions of five candidate genes for susceptibility to ETEC F4ab/ac infection (TFRC, ACK1, MUC20, MUC4 and KIAA0226), all located in the 2.5 Mb region, were investigated for the presence of possible causative mutations. A total of 34 polymorphisms were identified in either coding regions or their flanking introns. The genotyping data for two of those were found to perfectly match the genotypes at the ETEC F4ab/ac locus, a G to C polymorphism in intron 11 of TFRC and a C to T silent polymorphism in exon 22 of KIAA0226. Transcriptional profiles of the five genes were investigated in a porcine tissue panel including various intestinal tissues. All five genes were expressed in intestinal tissues at different levels but none of the genes were found differentially expressed between ETEC F4ab/ac resistant and ETEC F4ab/ac susceptible animals in any of the tested tissues. None of the identified polymorphisms are obvious causative mutations for ETEC F4ab/ac susceptibility, as they have no impact on the level of the overall mRNA expression nor predicted to influence the composition of the amino acids composition. However, we cannot exclude that the five tested genes are bona fide candidate genes for susceptibility to ETEC F4ab/ac infection since the identified polymorphism might affect the translational apparatus, alternative splice forms may exist and post translational mechanisms might contribute to disease susceptibility.
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2.94Impact points
The receptor locus for Escherichia coli F4ab/F4ac in the pig maps distal to the MUC4-LMLN region.
Mammalian genome : official journal of the International Mammalian Genome Society. 02/2011; 22(1-2):122-9.
Enterotoxigenic Escherichia coli (ETEC) with fimbriae of the F4 family are one of the major causes of diarrhea and death among neonatal and young piglets. Bacteria use the F4 fimbriae to adhere to specific receptors expressed on the surface of the enterocytes. F4 fimbriae exist in three different an... [more] Enterotoxigenic Escherichia coli (ETEC) with fimbriae of the F4 family are one of the major causes of diarrhea and death among neonatal and young piglets. Bacteria use the F4 fimbriae to adhere to specific receptors expressed on the surface of the enterocytes. F4 fimbriae exist in three different antigenic variants, F4ab, F4ac, and F4ad, of which F4ac is the most common. Resistance to ETEC F4ab/F4ac adhesion in pigs has been shown to be inherited as an autosomal recessive trait. In previous studies the ETEC F4ab/F4ac receptor locus (F4bcR) was mapped to the q41 region on pig chromosome 13. A polymorphism within an intron of the mucin 4 (MUC4) gene, which is one of the possible candidate genes located in this region, was shown earlier to cosegregate with the F4bcR alleles. Recently, we discovered a Large White boar from a Swiss experimental herd with a recombination between F4bcR and MUC4. A three-generation pedigree including 45 offspring was generated with the aim to use this recombination event to refine the localization of the F4bcR locus. All pigs were phenotyped using the microscopic adhesion test and genotyped for a total of 59 markers. The recombination event was mapped to a 220-kb region between a newly detected SNP in the leishmanolysin-like gene (LMLN g.15920) and SNP ALGA0072075. In this study the six SNPs ALGA0072075, ALGA0106330, MUC13-226, MUC13-813, DIA0000584, and MARC0006918 were in complete linkage disequilibrium with F4bcR. Based on this finding and earlier investigations, we suggest that the locus for F4bcR is located between the LMLN locus and microsatellite S0283.
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4.41Impact points
MicroRNA expression profiling of the porcine developing brain.
PloS one. 01/2011; 6(1):e14494.
MicroRNAs are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level and play an important role in the control of developmental and physiological processes. In particular, the developing brain contains an impressive diversity of microRNAs. Most microRNA expre... [more] MicroRNAs are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level and play an important role in the control of developmental and physiological processes. In particular, the developing brain contains an impressive diversity of microRNAs. Most microRNA expression profiling studies have been performed in human or rodents and relatively limited knowledge exists in other mammalian species. The domestic pig is considered to be an excellent, alternate, large mammal model for human-related neurological studies, due to its similarity in both brain development and the growth curve when compared to humans. Considering these similarities, studies examining microRNA expression during porcine brain development could potentially be used to predict the expression profile and role of microRNAs in the human brain. MicroRNA expression profiling by use of microRNA microarrays and qPCR was performed on the porcine developing brain. Our results show that microRNA expression is regulated in a developmentally stage-specific, as well as a tissue-specific manner. Numerous developmental stage or tissue-specific microRNAs including, miR-17, miR-18a, miR-29c, miR-106a, miR-135a and b, miR-221 and miR-222 were found by microarray analysis. Expression profiles of selected candidates were confirmed by qPCR. The differential expression of specific microRNAs in fetal versus postnatal samples suggests that they likely play an important role in the regulation of developmental and physiological processes during brain development. The data presented here supports the notion that microRNAs act as post-transcriptional switches which may regulate gene expression when required.
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0.81Impact points
Investigation of tissue-specific human orthologous alternative splice events in pig.
Animal biotechnology. 10/2010; 21(4):203-16.
Alternative splicing of pre-mRNA can contribute to differences between tissues or cells either by regulating gene expression or creating proteins with various functions encoded by one gene. The number of investigated alternative splice events in pig has so far been limited. In this study we have inv... [more] Alternative splicing of pre-mRNA can contribute to differences between tissues or cells either by regulating gene expression or creating proteins with various functions encoded by one gene. The number of investigated alternative splice events in pig has so far been limited. In this study we have investigated alternative splice events detected in humans, in orthologous pig genes. A total of 17 genes with predicted exon skipping events were selected for further studies. The splice events for the selected genes were experimentally verified using real-time quantitative PCR analysis (qPCR) with splice-specific primers in 19 different tissues. The same splice variants as reported in humans were detected in 15 orthologous pig genes, however, the expression pattern predicted in the in silico analyses was only experimentally verified in a few cases. The results support the findings that splice events resulting in preservation of open reading frame are indicative of a functional significance of the splice variants of the gene.
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1.09Impact points
Expression profiles of miRNA-122 and its target CAT1 in minipigs (Sus scrofa) fed a high-cholesterol diet.
Comparative medicine. 04/2010; 60(2):136-41.
The Göttingen minipig is an excellent model for studying effects of dietary high-fat intake on obesity. In this study, we analyzed the expression level of microRNA-122 (miRNA-122) and its target mRNA, CAT1, in intact young male minipigs fed either high-cholesterol or standard diet for 11 wk. MiRNA-1... [more] The Göttingen minipig is an excellent model for studying effects of dietary high-fat intake on obesity. In this study, we analyzed the expression level of microRNA-122 (miRNA-122) and its target mRNA, CAT1, in intact young male minipigs fed either high-cholesterol or standard diet for 11 wk. MiRNA-122 and CAT1 are known to be important regulators of lipid metabolism. The weight of the young minipigs was monitored once a week during the feeding period; measurements of total cholesterol, triglycerides, high-density lipoproteins, and low-density lipoproteins were recorded at 4 time points (8, 14, 16, and 19 wk of age) in fasting animals during the feeding scheme. Body weight, total cholesterol, and high-density lipoproteins were higher in pigs fed the high-cholesterol compared with the standard diet. In contrast, the level of triglycerides was lower in pigs on the high-cholesterol diet than those receiving the standard diet. Pigs fed high-cholesterol also had lower miRNA-122 levels than did those fed the standard diet. These results suggest that in our minipigs, the increase in weight and cholesterol levels resulting from subchronic (11 wk) feeding of a high-cholesterol diet is correlated with a decrease in the expression of miRNA-122, confirming the implication of this microRNA in obesity. Gene expression levels of CAT1 did not differ between groups.
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Pig genome sequence - analysis and publication strategy
BMC Genomics. 01/2010;
Abstract Background The pig genome is being sequenced and characterised under the auspices of the Swine Genome Sequencing Consortium. The sequencing strategy followed a hybrid approach combining hierarchical shotgun sequencing of BAC clones and whole genome shotgun sequencing. Results Assemblies... [more] Abstract Background The pig genome is being sequenced and characterised under the auspices of the Swine Genome Sequencing Consortium. The sequencing strategy followed a hybrid approach combining hierarchical shotgun sequencing of BAC clones and whole genome shotgun sequencing. Results Assemblies of the BAC clone derived genome sequence have been annotated using the Pre-Ensembl and Ensembl automated pipelines and made accessible through the Pre-Ensembl/Ensembl browsers. The current annotated genome assembly (Sscrofa9) was released with Ensembl 56 in September 2009. A revised assembly (Sscrofa10) is under construction and will incorporate whole genome shotgun sequence (WGS) data providing > 30× genome coverage. The WGS sequence, most of which comprise short Illumina/Solexa reads, were generated from DNA from the same single Duroc sow as the source of the BAC library from which clones were preferentially selected for sequencing. In accordance with the Bermuda and Fort Lauderdale agreements and the more recent Toronto Statement the data have been released into public sequence repositories (Genbank/EMBL, NCBI/Ensembl trace repositories) in a timely manner and in advance of publication. Conclusions In this marker paper, the Swine Genome Sequencing Consortium (SGSC) sets outs its plans for analysis of the pig genome sequence, for the application and publication of the results.
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A study of alternative splicing in the pig
BMC Research Notes. 01/2010;
Abstract Background Since at least half of the genes in mammalian genomes are subjected to alternative splicing, alternative pre-mRNA splicing plays an important contribution to the complexity of the mammalian proteome. Expressed sequence tags (ESTs) provide evidence of a great number of possible ... [more] Abstract Background Since at least half of the genes in mammalian genomes are subjected to alternative splicing, alternative pre-mRNA splicing plays an important contribution to the complexity of the mammalian proteome. Expressed sequence tags (ESTs) provide evidence of a great number of possible alternative isoforms. With the EST resource for the domestic pig now containing more than one million porcine ESTs, it is possible to identify alternative splice forms of the individual transcripts in this species from the EST data with some confidence. Results The pig EST data generated by the Sino-Danish Pig Genome project has been assembled with publicly available ESTs and made available in the PigEST database. Using the Distiller package 2,515 EST clusters with candidate alternative isoforms were identified in the EST data with high confidence. In agreement with general observations in human and mouse, we find putative splice variants in about 30% of the contigs with more than 50 ESTs. Based on the criteria that a minimum of two EST sequences confirmed each splice event, a list of 100 genes with the most distinct tissue-specific alternative splice events was generated from the list of candidates. To confirm the tissue specificity of the splice events, 10 genes with functional annotation were randomly selected from which 16 individual splice events were chosen for experimental verification by quantitative PCR (qPCR). Six genes were shown to have tissue specific alternatively spliced transcripts with expression patterns matching those of the EST data. The remaining four genes had tissue-restricted expression of alternative spliced transcripts. Five out of the 16 splice events that were experimentally verified were found to be putative pig specific. Conclusions In accordance with human and rodent studies we estimate that approximately 30% of the porcine genes undergo alternative splicing. We found a good correlation between EST predicted tissue-specificity and experimentally validated splice events in different porcine tissue. This study indicates that a cluster size of around 50 ESTs is optimal for in silico detection of alternative splicing. Although based on a limited number of splice events, the study supports the notion that alternative splicing could have an important impact on species differentiation since 31% of the splice events studied appears to be species specific.
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3.76Impact points
Pig genome sequence--analysis and publication strategy.
BMC genomics. 01/2010; 11:438.
The pig genome is being sequenced and characterised under the auspices of the Swine Genome Sequencing Consortium. The sequencing strategy followed a hybrid approach combining hierarchical shotgun sequencing of BAC clones and whole genome shotgun sequencing. Assemblies of the BAC clone derived genome... [more] The pig genome is being sequenced and characterised under the auspices of the Swine Genome Sequencing Consortium. The sequencing strategy followed a hybrid approach combining hierarchical shotgun sequencing of BAC clones and whole genome shotgun sequencing. Assemblies of the BAC clone derived genome sequence have been annotated using the Pre-Ensembl and Ensembl automated pipelines and made accessible through the Pre-Ensembl/Ensembl browsers. The current annotated genome assembly (Sscrofa9) was released with Ensembl 56 in September 2009. A revised assembly (Sscrofa10) is under construction and will incorporate whole genome shotgun sequence (WGS) data providing > 30x genome coverage. The WGS sequence, most of which comprise short Illumina/Solexa reads, were generated from DNA from the same single Duroc sow as the source of the BAC library from which clones were preferentially selected for sequencing. In accordance with the Bermuda and Fort Lauderdale agreements and the more recent Toronto Statement the data have been released into public sequence repositories (Genbank/EMBL, NCBI/Ensembl trace repositories) in a timely manner and in advance of publication. In this marker paper, the Swine Genome Sequencing Consortium (SGSC) sets outs its plans for analysis of the pig genome sequence, for the application and publication of the results.
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A study of alternative splicing in the pig.
BMC research notes. 01/2010; 3:123.
Since at least half of the genes in mammalian genomes are subjected to alternative splicing, alternative pre-mRNA splicing plays an important contribution to the complexity of the mammalian proteome. Expressed sequence tags (ESTs) provide evidence of a great number of possible alternative isoforms. ... [more] Since at least half of the genes in mammalian genomes are subjected to alternative splicing, alternative pre-mRNA splicing plays an important contribution to the complexity of the mammalian proteome. Expressed sequence tags (ESTs) provide evidence of a great number of possible alternative isoforms. With the EST resource for the domestic pig now containing more than one million porcine ESTs, it is possible to identify alternative splice forms of the individual transcripts in this species from the EST data with some confidence. The pig EST data generated by the Sino-Danish Pig Genome project has been assembled with publicly available ESTs and made available in the PigEST database. Using the Distiller package 2,515 EST clusters with candidate alternative isoforms were identified in the EST data with high confidence. In agreement with general observations in human and mouse, we find putative splice variants in about 30% of the contigs with more than 50 ESTs. Based on the criteria that a minimum of two EST sequences confirmed each splice event, a list of 100 genes with the most distinct tissue-specific alternative splice events was generated from the list of candidates. To confirm the tissue specificity of the splice events, 10 genes with functional annotation were randomly selected from which 16 individual splice events were chosen for experimental verification by quantitative PCR (qPCR). Six genes were shown to have tissue specific alternatively spliced transcripts with expression patterns matching those of the EST data. The remaining four genes had tissue-restricted expression of alternative spliced transcripts. Five out of the 16 splice events that were experimentally verified were found to be putative pig specific. In accordance with human and rodent studies we estimate that approximately 30% of the porcine genes undergo alternative splicing. We found a good correlation between EST predicted tissue-specificity and experimentally validated splice events in different porcine tissue. This study indicates that a cluster size of around 50 ESTs is optimal for in silico detection of alternative splicing. Although based on a limited number of splice events, the study supports the notion that alternative splicing could have an important impact on species differentiation since 31% of the splice events studied appears to be species specific.
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0.81Impact points
Expression studies of the obesity candidate gene FTO in pig.
Animal biotechnology. 01/2010; 21(1):51-63.
Obesity is an increasing problem worldwide and research on candidate genes in good animal models is highly needed. The pig is an excellent model as its metabolism, organ size, and eating habits resemble that of humans. The present study is focused on the characterization of the fat mass and obesity ... [more] Obesity is an increasing problem worldwide and research on candidate genes in good animal models is highly needed. The pig is an excellent model as its metabolism, organ size, and eating habits resemble that of humans. The present study is focused on the characterization of the fat mass and obesity associated gene (FTO) in pig. This gene has recently been associated with increased body mass index in several human populations. To establish information on the expression profile of FTO in the pig we performed quantitative PCR in a panel of adult pig tissues and in tissues sampled at different developmental stages. Expression of the FTO transcript was detected in all tissues tested with significantly higher levels in brain tissues (cortex, cerebellum, and hippocampus; P < 0.001). These levels varied through the development and between the specific parts of the brain studied (i.e., frontal cortex and cerebellum). Additionally, in order to see the involvement of the FTO gene in obesity, the changes in expression level were investigated in a nutritional study in brain of Gottingen minipigs under a high cholesterol diet. Significantly higher (P < 0.01) levels of FTO transcript were found in cortex when compared with cerebellum of the high-cholesterol fed pigs. Furthermore, SNPs were investigated in the coding sequence of the FTO in the Gottingen minipig and in the Danish commercial pig. Eleven synonymous SNPs and a two bp insertion were found between the two pig lines.
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1.13Impact points
POPULATION DYNAMICS OF ASCARIS SUUM IN TRICKLE INFECTED PIGS.
The Journal of parasitology. 09/2009;
The population dynamics of Ascaris suum was studied by long term exposure of pigs to infective eggs. The pigs were experimentally inoculated with 25 A. suum eggs/kg/day, and 7, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 post inoculation (p.i.), respectively. Despite that pigs were continuou... [more] The population dynamics of Ascaris suum was studied by long term exposure of pigs to infective eggs. The pigs were experimentally inoculated with 25 A. suum eggs/kg/day, and 7, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 post inoculation (p.i.), respectively. Despite that pigs were continuously reinfected, dramatic reductions in numbers of liver lesions (white spots) and migrating lung larvae were observed as a function of time. However, even at the end of the study a few larvae were found to be able to complete migration, but these larvae seemed unable to grow up in the small intestine. Thus, the adult worm population seemed to consist of worms from the first part of the exposure period. The noticeable decrease in number of white spots suggests that the level of exposure is not reflected in the number of white spots in the late phase of a continuous infection. The serum levels of A. suum L3 specific IgG1 and IgA were significantly elevated by week 4 p.i. where after the antibody levels declined. The population dynamics and possible parasite regulating mechanisms are discussed for A.suum in pigs as well as for the closely related species A. lumbricoides in man.
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2.28Impact points
A novel technique for identification of Ascarissuum cohorts in pigs.
Veterinary parasitology. 07/2008; 154(1-2):171-4.
The objective of the present study was to develop a fast, cheap and reliable technique for identifying different cohorts of the swine parasite, Ascaris suum. A polymerase chain reaction linked restriction fragment length polymorphism (PCR-RFLP) technique on mt-DNA was used to identify unique haploty... [more] The objective of the present study was to develop a fast, cheap and reliable technique for identifying different cohorts of the swine parasite, Ascaris suum. A polymerase chain reaction linked restriction fragment length polymorphism (PCR-RFLP) technique on mt-DNA was used to identify unique haplotypes of four gravid A. suum females on agarose gels after eggs were recovered from each of the worms. Each of four pigs was inoculated with 2000 embryonated eggs originating from one of the four identified Ascaris haplotypes, respectively. Ascaris larvae were isolated from the small intestine at day 14 post-infection using an agar technique. Single larvae from each pig were transferred to 96-well PCR plates and a simple DNA extraction using a worm lysis buffer was carried out and followed by the PCR-RFLP analysis. More than 100 larvae from each of the four pigs were analysed and all were found to have the same haplotype as the parental female. We conclude that unique haplotypes of female A. suum and offspring can be identified by means of PCR-RFLP on mt-DNA and suggest that this method can be used in future research on Ascaris population biology using cohorts with distinct mt-DNA profile.
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34.28Impact points
Highly effective SNP-based association mapping and management of recessive defects in livestock.
Nature genetics. 05/2008; 40(4):449-54.
The widespread use of elite sires by means of artificial insemination in livestock breeding leads to the frequent emergence of recessive genetic defects, which cause significant economic and animal welfare concerns. Here we show that the availability of genome-wide, high-density SNP panels, combined... [more] The widespread use of elite sires by means of artificial insemination in livestock breeding leads to the frequent emergence of recessive genetic defects, which cause significant economic and animal welfare concerns. Here we show that the availability of genome-wide, high-density SNP panels, combined with the typical structure of livestock populations, markedly accelerates the positional identification of genes and mutations that cause inherited defects. We report the fine-scale mapping of five recessive disorders in cattle and the molecular basis for three of these: congenital muscular dystony (CMD) types 1 and 2 in Belgian Blue cattle and ichthyosis fetalis in Italian Chianina cattle. Identification of these causative mutations has an immediate translation into breeding practice, allowing marker assisted selection against the defects through avoidance of at-risk matings.
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3.76Impact points
Phenotypic and genetic characterization of a novel phenotype in pigs characterized by juvenile hairlessness and age dependent emphysema.
BMC genomics. 02/2008; 9:283.
BACKGROUND: A pig phenotype characterized by juvenile hairlessness, thin skin and age dependent lung emphysema has been discovered in a Danish pig herd. The trait shows autosomal co-dominant inheritance with all three genotypes distinguishable. Since the phenotype shows resemblance to the integrin b... [more] BACKGROUND: A pig phenotype characterized by juvenile hairlessness, thin skin and age dependent lung emphysema has been discovered in a Danish pig herd. The trait shows autosomal co-dominant inheritance with all three genotypes distinguishable. Since the phenotype shows resemblance to the integrin beta6 -/- knockout phenotype seen in mice, the two genes encoding the two subunits of integrin alphavbeta6, i.e. ITGB6 and ITGAV, were considered candidate genes for this trait. RESULTS: The mutated pig phenotype is characterized by hairlessness until puberty, thin skin with few hair follicles and absence of musculi arrectores pili, and at puberty or later localized areas of emphysema are seen in the lungs. Comparative mapping predicted that the porcine ITGB6 andITGAV orthologs map to SSC15. In an experimental family (n = 113), showing segregation of the trait, the candidate region was confirmed by linkage analysis with four microsatellite markers. Mapping of the porcine ITGB6 and ITGAV in the IMpRH radiation hybrid panel confirmed the comparative mapping information. Sequencing of the ITGB6 and ITGAV coding sequences from affected and normal pigs revealed no evidence of a causative mutation, but alternative splicing of the ITGB6 pre-mRNA was detected. For both ITGB6 and ITGAV quantitative PCR revealed no significant difference in the expression levels in normal and affected animals. In a western blot, ITGB6 was detected in lung protein samples of all three genotypes. This result was supported by flow cytometric analyses which showed comparable reactions of kidney cells from affected and normal pigs with an integrin alphavbeta6 monoclonal antibody. Also, immunohistochemical staining of lung tissue with an integrin beta6 antibody showed immunoreaction in both normal and affected pigs. CONCLUSION: A phenotype resembling the integrin beta6 -/- knockout phenotype seen in mice has been characterized in the pig. The candidate region on SSC15 has been confirmed by linkage analysis but molecular and functional analyses have excluded that the mutated phenotype is caused by structural mutations in or ablation of any of the two candidate genes.
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2.23Impact points
Genome-wide identification of quantitative trait loci in a cross between Hampshire and Landrace II: meat quality traits.
BMC genetics. 02/2008; 9:22.
BACKGROUND: Meat quality traits are important in pig breeding programs, but they are difficult to include in a traditional selection program. Marker assisted selection (MAS) of meat quality traits is therefore of interest in breeding programs and a Quantitative Trait Locus (QTL) analysis is the key ... [more] BACKGROUND: Meat quality traits are important in pig breeding programs, but they are difficult to include in a traditional selection program. Marker assisted selection (MAS) of meat quality traits is therefore of interest in breeding programs and a Quantitative Trait Locus (QTL) analysis is the key to identifying markers that can be used in MAS. In this study, Landrace and Hampshire intercross and backcross families were used to investigate meat quality traits. Hampshire pigs are commonly used as the sire line in commercial pig breeding. This is the first time a pedigree including Hampshire pigs has been used for a QTL analysis of meat quality traits. RESULTS: In total, we analyzed 39 meat quality traits and identified eight genome-wide significant QTL peaks in four regions: one on chromosome 3, two on chromosome 6 and one on chromosome 16. At least two of the QTLs do not appear to have been detected in previous studies. On chromosome 6 we identified QTLs for water content in M. longissimus dorsi (LD), drip loss in LD and post mortem pH decline in LD. On chromosomes 3 and 16 we identified previously undetected QTLs for protein content in LD and for freezing and cooking loss respectively. CONCLUSION: We identified at least two new meat quality trait QTLs at the genome-wide significance level. We detected two QTLs on chromosome 6 that possibly coincide with QTLs detected in other studies. We were also able to exclude the C1843T mutation in the ryanodine receptor (RYR1) as a causative mutation for one of the chromosome 6 QTLs in this cross.
Following (13)
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Claus Bøttcher Jørgensen
University of Copenhagen -
Ake Hedhammar
Sveriges Lantbruksuniversitet -
Kirsten Harvey
Institute of Child Health -
Terje Raudsepp
Texas A&M University -
Silvia Braglia
Alma Mater Studiorum Università di Bologna
