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From QTL to QTN

identification of a quantitative trait nucleotide influencing muscle development and fat deposition in pig

Laere, Anne-Sophie van (2005). From QTL to QTN. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2005:9
ISBN 91-576-7008-0
[Doctoral thesis]

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Most traits of economical importance in animal production are quantitative i.e. they are characterized by a continuous variation of phenotypic values. Examples for such traits are carcass weight, milk production and lean meat content. The phenotype of an animal for a quantitative trait depends on its genotype at several loci (called quantitative trait loci, QTL) as well as on environmental factors. Up to date, a large number of QTLs have been identified in farm animals by segregation analysis either within commercial populations or in crossbreed populations. Animal geneticists face now the challenge to identify the causative mutations lying behind these QTLs. In this thesis, we report the identification of the causative mutation for a major QTL influencing muscle development, fat deposition and heart size in pig. Previous studies have mapped this locus to the distal end of pig chromosome 2p. Furthermore, they have hypothesized that the causative mutation(s) may lie in an element regulating the expression of insulin-like growth factor 2 (IGF2). Firstly, we sequenced the IGF2 region in the pig and made comparative sequence analysis with available human and mouse sequences. We then used an identity-by-descent approach and managed to pinpoint the causative mutation to a G‡A transition located in an evolutionary conserved CpG island in IGF2 intron 3 (IGF2-intron3-G3070A). Subsequently, we used electrophoretic mobility shift assay and transient transfection experiments and showed that the QTN (quantitative trait nucleotide) abrogates the binding of a putative repressor. We completed our study by determining the core binding site of this transacting factor and by performing DNase I footprinting of the CpG island containing the QTN. In addition, we identified an IGF2 antisense transcript (IGF2-AS) and showed that its expression was also influenced by the QTN. The discovery of mutations causing QTLs in farm animals opens great future prospects. Besides evident practical breeding interests there are also major scientific interests, as understanding the mechanism causing the QTL effects will broaden our general knowledge on how the genome operates.

Authors/Creators:Laere, Anne-Sophie van
Title:From QTL to QTN
Subtitle:identification of a quantitative trait nucleotide influencing muscle development and fat deposition in pig
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :January 2005
Number of Pages:32
ALLI. Amarger, V., Nguyen, M., Van Laere, A.S., Braunschweig, M., Nezer, C., Georges, M. & Andersson, L. 2002. Comparative sequence analysis of the INS-IGF2-H19 gene cluster in pigs. Mammelian Genome 13, 388-398. II. Van Laere, A.S., Nguyen, M., Braunschweig, M., Nezer, C., Collette, C., Moreau, L., Archibald, A.L., Haley, C.S., Buys, N., Tally, M., Andersson, G., Georges, M. & Andersson, L. 2003. A regulatory mutation in IGF2 causes a major QTL effect on muscle growth in the pig. Nature 425, 832-836. III. Braunschweig, M.H., Van Laere, A.S., Buys, N., Andersson, L. & Andersson, G. 2004. IGF2 antisense transcript expression in porcine postnatal muscle is affected by a quantitative trait nucleotide in intron 3. Genomics 84, 1021-1029. IV. Van Laere, A.S., Andersson, G., Kindmark, A. & Andersson, L. Molecular Characterization of a Region in IGF2 Intron 3 harbouring a Quantitative Trait Nucleotide affecting Muscle Growth in the Pig. (Manuscript).
Place of Publication:Uppsala
ISBN for printed version:91-576-7008-0
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L10 Animal genetics and breeding
Subjects:Not in use, please see Agris categories
Agrovoc terms:transcription, gene expression, nucleotides, muscles, fats, genetics, wild boar
Keywords:antisense transcript, CpG island, quantitative trait locus, quantitative trait nucleotide, repressor, Sus scrofa
Permanent URL:
ID Code:719
Department:(VH) > Dept. of Animal Breeding and Genetics
Deposited By: Anne-Sophie Van Laere
Deposited On:26 Jan 2005 00:00
Metadata Last Modified:02 Dec 2014 10:06

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