Identification of functional candidate genes for body composition by expression analyses and evidencing impact by association analysis and mapping.
This study aims to identify hepatic genes affecting traits related to muscularity and obesity by combining expression analyses, association studies, and gene mapping. Functional candidate genes with trait-associated expression were obtained by hybridising custom made application-specific cDNA microarrays with targets of discordant sib pairs of a porcine experimental population. Out of 238 genes addressed, nine genes were regulated by the factor>or=2 between the sib pairs. Differential gene expression was independently confirmed for selected genes by real time RT-PCR. Transcript levels of four genes (APOH, PEDF, SLCO1B3, TBG) were significantly different between the phenotype groups. Screening for trait associated markers within TBG and APOH by comparative sequencing of discordant sib pairs revealed a SNP at position nt 778 (A>C) (N229H) of TBG. No polymorphism in APOH was detected. Association analysis confirmed effects of TBG on carcass traits statistically. Allocating TBG to a QTL region on chromosome X revealed genetic evidence for the effect. Moreover, our results indicate that there are probably two polymorphisms segregating-one (N229H) altering binding capability of TBG and another still to be detected altering the transcription rate of TBG.
Ponsuksili
Siriluck
S
Institute of Animal Breeding and Genetics, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany; Research Institute for the Biology of Farm Animals, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany.
Murani
Eduard
E
Schellander
Karl
K
Schwerin
Manfred
M
Wimmers
Klaus
K
D000704:Analysis of Variance; D000818:Animals; D001823:Body Composition / Q000235:genetics*; D002874:Chromosome Mapping; D017931:DNA Primers; D020869:Gene Expression Profiling; D005796:Genes / Q000235:genetics*; D016014:Linear Models; D008099:Liver / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D034421:Sus scrofa / Q000235:genetics*
D017931:DNA Primers