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M Fredholm

Publications and source records attributed to M Fredholm.

At least 37 records · Page 2Linked to original sources
PubMed1998

Multiple marker mapping of quantitative trait loci in a cross between outbred wild boar and large white pigs.

A quantitative trait locus (QTL) analysis of growth and fatness data from a three generation pig experiment is presented. The population of 199 F2 animals was derived from a cross between wild boar and Large White pigs. Animals were typed for 240 markers spanning 23 Morgans of 18 autosomes and the X chromosome. A series of analyses are presented within a least squares framework. First, these identify chromosomes containing loci controlling trait variation and subsequently attempt to map QTLs to locations within chromosomes. This population gives evidence for a large QTL affecting back fat and another for abdominal fat segregating on chromosome 4. The best locations for these QTLs are within 4 cM of each other and, hence, this is likely to be a single QTL affecting both traits. The allele inherited from the wild boar causes an increase in fat deposition. A QTL for intestinal length was also located in the same region on chromosome 4 and could be the same QTL with pleiotropic effects. Significant effects, owing to multiple QTLs, for intestinal length were identified on chromosomes 3 and 5. A single QTL affecting growth rate to 30 kg was located on chromosome 13 such that the Large White allele increased early growth rate, another QTL on chromosome 10 affected growth rate from 30 to 70 kg and another on chromosome 4 affected growth rate to 70 kg.

Animals↗
PubMed1997

Mapping of 22 expressed sequence tags isolated from a porcine small intestine cDNA library.

Complementary DNA sequences were selected from a resource of tentatively identified clones from a porcine small intestine cDNA library. Forty PCR primer pairs were designed to amplify 101-309 base pairs of the 3' untranslated region of the genes. The PCR conditions were optimized by altering both formamide and magnesium concentrations on samples of pig, mouse, and hamster DNA. Twenty primer pairs that, under stringent conditions, were pig-specific and amplified the expected fragments were chosen for regional assignment in a pig/rodent hybrid cell panel. Furthermore, 22 primer pairs were chosen to amplify DNA from the parental animals of the PiGMaP shared reference families in order to detect possible polymorphisms. Primer pairs that generated polymorphisms were used for genetic mapping. A total of 22 porcine expressed sequence tags (ESTs) were cytogenetically or genetically mapped by this approach. Twelve of the mapped ESTs could be added to the human-porcine comparative map.

Animals↗
PubMed1997

Expansion of the pig comparative map by expressed sequence tags (EST) mapping.

We have used a PCR-based approach for the genetical and physical mapping of 34 transcripts isolated from a porcine small intestine cDNA library. All but one gene were regionally localized by using a somatic pig-rodent cell hybrid panel, and 12 genes were mapped by linkage analysis of single-stranded conformational polymorphisms developed in 3' untranslated regions of transcripts. For 20 of the transcripts, the human homolog has already been mapped. This study thus represents a significant contribution to the pig comparative map. Some important findings were that we could clarify the extent of a previously identified inversion event in a region of conserved synteny between SSC6q and HSA1p, that SSC14q does contain a region homologous to HSA1, a situation not clear from earlier ZOO-FISH studies, and that the homology between SSC17 and HSA20 includes the p-arm of HSA20.

Animals↗
PubMed1997

FISH mapping of seven cDNA sequences in the pig.

Fluorescence in situ hybridization (FISH) technique was applied to localize seven clones derived from a porcine (SSC) intestinal directionally cloned cDNA library. The size of the clones ranged from 1.1 to 1.3 kb. Three of the clones corresponded to histidyl-tRNA synthetase (HARS), immunoglobulin alpha (IGA) and lysozyme (LYZ) and mapped to SSC2q28-q29, 7q2.6 and 5p11 respectively. The available human-pig comparative painting data and sequence homology comparisons assisted in a tentative identification of the other three clones as glutathione-S-transferase (GST), glutathione-S-transferase mu (GSTM1) and immunoglobulin lambda gene cluster (IGL@). These clones mapped to SSC14q21, 5q2.4 and 14q22-q23 respectively. The remaining clone representing an EST mapped to 1p24-p25. These localizations contribute to the transcript map in pig and are significant as comparative markers. Difficulties associated with the mapping of small sequences using FISH are discussed.

Animals↗
PubMed1997

A study of mixing conditions during nitric oxide administration using simultaneous fast response chemiluminescence and capnography.

We have evaluated the mixing properties of nitric oxide in inspired gases for five different administration techniques. Nitric oxide and carbon dioxide were delivered to the ventilator system before the ventilator or after the ventilator as a continuous flow, either directly into the inspiratory limb or into a mixing chamber positioned in the inspiratory limb. Both gases were delivered as above but synchronized with inspiration. Mixing conditions were evaluated using fast response chemiluminescence for nitric oxide and capnography for carbon dioxide analysis. Administration of nitric oxide and carbon dioxide directly into the inspiratory limb as a continuous flow or with a magnetic valve-controlled synchronized flow resulted in peak concentrations of 236% and 220%, respectively, of expected values. The use of a mixing chamber reduced these values to 104% and 102%, respectively. Administration of nitric oxide as a continuous flow into the tubing of an intermittent flow ventilator resulted in highly fluctuating inspiratory peak concentrations, which could be avoided with a mixing chamber.

Capnography↗
PubMed1996

Evaluation and characterization of a porcine small intestine cDNA library: analysis of 839 clones.

A porcine small intestine directionally cloned cDNA library was constructed in the vector lambda Zap II. Clones were hybridized with total labeled cDNA such that putative high-copy number transcripts could be differentiated from middle- and low-copy number transcripts prior to selection and characterization by DNA sequencing. More than 2000 non-hybridizing and 242 hybridizing clones were collected. In total, 839 clones were sequenced from the 3' end of the cDNA, and after inter-clone comparison, the unique clones were sequenced from the 5' end of the cDNA. The 5' data were used to query the sequence in databases and resulted in the identification of 630 different gene transcripts, of which 604 are new porcine genes. The identity of 361 transcripts could be identified from sequence comparison studies. The validity of this semi-random selection approach was verified by the identification of a large number of unique transcripts.

Animals↗
PubMed1996

A comprehensive linkage map of the pig based on a wild pig-Large White intercross.

A comprehensive linkage map, including 236 linked markers with a total sex-average map length of about 2300 cM, covering nearly all parts of the pig genome has been established. Linkage groups were assigned to approximately all 18 autosomes, the X chromosome and the X/Y pseudoautosomal region. Several new gene assignments were made including the assignment of linkage group U1 (EAK-HPX) to chromosome 9. The linkage map includes 77 types I loci informative for comparative mapping and 72 in situ mapped markers physically anchoring the linkage groups on chromosomes. A highly significant heterogeneity in recombination rates between sexes was observed with a general tendency towards an excess of female recombination. The average ratio of female to male recombination was estimated at 1.4:1 but this parameter varied between chromosomes as well as between regions within chromosomes. An intriguing finding was that blood group loci were overrepresented at the distal ends of linkage groups.

Animals↗
PubMed1996

Efficient resolution of parentage in dogs by amplification of microsatellites.

Parentage control has been performed for 15 litters from 12 different dog breeds by amplification of microsatellites. As it was possible to include all putative parents in all cases, they were solved by exclusion. Discrimination between parents/non-parents was made after genotyping of 6-9 microsatellite loci. In 12 of the cases all but one of the alleged fathers were excluded while in three cases it was unambiguously shown that superfecundation had taken place. Furthermore, one inclusion case concerning disputed maternity has been investigated. Maternity indices were calculated for 12 loci and probability of maternity was estimated to be 99.99%. These results testify that microsatellites can be applied very efficiently for resolution of parentage in dogs.

Alleles↗
PubMed1995

Variation of short tandem repeats within and between species belonging to the Canidae family.

Frequency distribution and allele size in 20 canine microsatellite loci were analyzed in 33 flat-coated retrievers, 32 dachshunds, 10 red foxes, and 10 Arctic foxes. Overall, the major difference between the two dog breeds was the relative allele frequencies rather than the size ranges of alleles at the individual locus. The average heterozygosity within the two dog breeds was not significantly different. Since the average heterozygosity at several polymorphic loci is a relative measure of heterogeneity within the population, analysis of heterozygosity within microsatellite loci is suggested as a measure for the diversity of populations. Eighty percent (16 of 20) of the canine microsatellite primer pairs amplified corresponding loci in the two fox species. This reflects a very high sequence conservation within the Canidae family relative to findings in, for instance, the Muridae family. This indicates that it will be possible to utilize the well-characterized fox karyotype instead of the dog karyotype as a step towards physical mapping of the dog genome. Analysis of exclusion power and probabilities of genetic identity between unrelated animals by use of the seven most informative loci demonstrated that it will be possible to assemble a panel of microsatellite loci that is effective for parentage analysis in all breeds.

Alleles↗
PubMed1994

A physically anchored linkage map of pig chromosome 1 uncovers sex- and position-specific recombination rates.

A linkage map of pig chromosome 1 (SSC1) has been constructed using 15 polymorphic markers. Eleven markers constitute PCR-based microsatellites (three associated with coding sequences), six markers have also been mapped by in situ hybridization, and homologues to four of the markers have been mapped in human. The physical assignments show that almost the entire SSC1 is covered by the linkage map, which measures 164 cM (sex-averaged). In a large region on the q arm, representing about 40% of the chromosome, there is a significant excess of male recombination. In contrast, there is a significantly higher recombination rate in females in both terminal regions. In the penultimate marker intervals on the q arm as well as the p arm, females show a fivefold excess of recombination compared to males. The rate of genetic recombination in relation to the physical DNA content is 1 cM per 2-4 Mb over at least 80% of the chromosome. In the terminal part of the q arm, however, there is a tremendous increase in the recombination rate, with 1 cM equaling about 0.4 Mb. Two homologous chromosome segments in human could be detected, ESR-CGA on human chromosome 6 (HSA6) and IFNA-RLN-GRP78 on human chromosome 9 (HSA9). Since the porcine blood group locus EAA is located close to (or possibly within) the latter conserved segment and the suggested human counterpart, the ABO system, is similarly close to the segment on HSA9, our data provide indirect evidence that these blood group systems are homologous.

Animals↗
PubMed1994

Genetic mapping of quantitative trait loci for growth and fatness in pigs.

The European wild boar was crossed with the domesticated Large White pig to genetically dissect phenotypic differences between these populations for growth and fat deposition. The most important effects were clustered on chromosome 4, with a single region accounting for a large part of the breed difference in growth rate, fatness, and length of the small intestine. The study is an advance in genome analyses and documents the usefulness of crosses between divergent outbred populations for the detection and characterization of quantitative trait loci. The genetic mapping of a major locus for fat deposition in the pig could have implications for understanding human obesity.

Adipose Tissue↗
PubMed1994

A primary linkage map of the porcine genome reveals a low rate of genetic recombination.

A comprehensive genetic linkage map of the porcine genome has been developed by typing 128 genetic markers in a cross between the European Wild Boar and a domestic breed (Large White). The marker set includes 68 polymerase chain reaction-formatted microsatellites, 60 anchored reference markers informative for comparative mapping and 47 markers which have been physically assigned by in situ hybridization. Novel multipoint assignments are provided for 54 of the markers. The map covers about 1800 cM, and the average spacing between markers is 11 cM. We used the map data to estimate the genome size in pigs, thereby addressing the total recombination distance in a third mammalian species. A sex-average genome length of 1873 +/- 139 cM was obtained by comparing the recombinational and physical distances in defined regions of the genome. This is strikingly different from the length of the human genome (3800-4000 cM) and is more similar to the mouse estimate (1600 cM). The recombination rate in females was significantly higher than in males.

Animals↗
PubMed1994

Chromosomal assignment of porcine microsatellites by use of a somatic cell hybrid mapping panel.

A well-established and characterized somatic cell hybrid panel was used to map three polymorphic microsatellites. Microsatellite S0072, representing the linkage group S0007-S0072, was assigned to porcine chromosome 14. Microsatellite S0009, representing the unassigned linkage group EAM-S0009-S0071, was assigned tentatively to porcine chromosome 11. Finally, S0062 was tentatively mapped to chromosome 18. S0062 may represent the first marker for porcine chromosome 18.

Animals↗