Detection of quantitative trait loci for reproduction and production traits in Large White and French Landrace pig populations (Open Access publication)

et al. 2008

Animal

A quantitative trait locus (QTL) analysis of female reproductive data from a three-generation experimental cross between Meishan (MS) and Large White (LW) pig breeds is presented. Six F1 boars and 23 F1 sows, progeny of six LW boars and six MS sows, produced 573 F2 females and 530 F2 males. Six traits, i.e. teat number (TN), age at puberty (AP), ovulation rate (OR), weight at mating (WTM), number of viable embryos (NVE) and embryo survival (ES) at 30 days of gestation were analysed. Animals were genotyped for a total of 137 markers covering the entire porcine genome. Analyses were carried out based on interval mapping methods, using a line-cross (LC) regression and a half-full sib (HFS) maximum likelihood test. Genome-wide (GW) highly significant (P , 0.001) QTL were detected for WTM on SSC 7 and for AP on SSC 13. They explained, respectively, 14.5% and 8.9% of the trait phenotypic variance. Other GW significant (P , 0.05) QTL were detected for TN on SSC 3, 7, 8, 16 and 17, for OR on SSC 4 and 5, and for ES on SSC 9. Two additional chromosome-wide significant (P , 0.05) QTL were detected for TN, three for WTM, four for AP, three for OR, three for NVE and two for ES. With the exception of the two above-mentioned loci, the QTL explained from 1.2% to 4.6% of trait phenotypic variance. QTL alleles were in most cases not fixed in the grand-parental populations and Meishan alleles were not systematically associated with higher reproductive performance.

Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 95%

Detection of quantitative trait loci for teat number and female reproductive traits in Meishan × Large White F2 pigs

Bidanel

Rosendo

et al. 2008

Animal

“…Moreover, several QTL of the QTL regions identified in this study were found to carry reproduction QTL in other studies. For instance, the SSG6 QTL affecting the length of uterine horns was close to the QTL affecting litter size detected by Wilkie et al (1999), Tribout et al (2008), and Li et al (2009). The QTL affecting ovarian weight in the SW1354-SW1369 interval on SSG7 contains the properdin locus, which was shown to be associated with litter size at birth by Buske et al (2005).…”

Section: Discussionmentioning

confidence: 94%

Microsatellite mapping of quantitative trait loci affecting female reproductive tract characteristics in Meishan × Large White F2 pigs1

Rosendo

Journal of Animal Science

Gilbert

et al. 2012

A QTL analysis of female reproductive data from a 3-generation experimental cross between Meishan and Large White pig breeds is presented. Six F(1) boars and 23 F(1) sows, progeny of 6 Large White boars and 6 Meishan sows, produced 502 F(2) gilts whose reproductive tract was collected after slaughter at 30 d of gestation. Five traits [i.e., the total weight of the reproductive tract, of the empty uterine horns, of the ovaries (WOV), and of the embryos], as well as the length of uterine horns (LUH), were measured and analyzed with and without adjustment for litter size. Animals were genotyped for a total of 137 markers covering the entire porcine genome. Analyses were carried out based on interval mapping methods, using a line-cross regression and a half-full sib maximum likelihood test. A total of 18 genome-wide significant (P < 0.05) QTL were detected on 9 different chromosomes (i.e., SSC 1, 5, 6, 7, 9, 12, 13, 18, and X). Five genome-wide significant QTL were detected for LUH, 4 for weight of the empty uterine horns and WOV, 2 for total weight of the reproductive tract, and 1 for weight of the embryos. Twenty-two additional suggestive QTL were also detected. The largest effects were obtained for LUH and WOV on SSC13 (9.2 and 7.0% of trait phenotypic variance, respectively). Meishan alleles had both positive (e.g., on SSC7) and negative effects (e.g., on SSC13) on the traits investigated. Moreover, the QTL were generally not fixed in founder breeds, and opposite effects were in some cases obtained in different families. Although reproductive tract characteristics had only a moderate correlation with reproductive performances, most of the major QTL detected in this study were previously reported as affecting female reproduction, generally with reduced significance levels. This study thus shows that focusing on traits with high heritability might help to detect loci involved in low heritability major traits for breeding.

“…When QTL are detected in such populations, they cannot be directly used in selection programmes and additional studies are required to confirm the existence of these QTL in commercial populations. Nevertheless, genome scans are carried out on an increasing -E-mail: marie-pierre.sanchez@jouy.inra.fr number of crosses of commercial populations: Yorkshire 3 Berkshire (Malek et al, 2001a and2001b), Piétrain 3 Large White (Nezer et al, 2002), Iberian 3 Landrace (Varona et al, 2002), Hampshire 3 Landrace (Karlskov-Mortensen et al, 2005) or Duroc 3 Piétrain populations (Liu et al, 2007;Edwards et al, 2008a and2008b) and even on purebred commercial populations (Evans et al, 2003;Vidal et al, 2005;Tribout et al, 2008). All these studies revealed a large number of QTL, suggesting that different alleles are fixed in distinct commercial populations or that QTL are still segregating in purebred populations after many generations of selection.…”

Section: Introductionmentioning

confidence: 99%

Microsatellite mapping of quantitative trait loci affecting meat quality, stress hormones and production traits in Duroc × Large White F2 pigs

Sanchez

Basso

et al. 2011

Animal

An F2 cross between Duroc and Large White pigs was carried out in order to detect quantitative trait loci (QTL) for 11 meat quality traits (L*, a* and b* Minolta coordinates and water-holding capacity (WHC) of two ham muscles, ultimate pH of two ham and one loin muscles), 13 production traits (birth weight, average daily gain during post-weaning and fattening periods, carcass fat depths at three locations, estimated lean meat content, carcass length and weights of five carcass cuts) and three stress hormone-level traits (cortisol, adrenaline and noradrenaline). Animals from the three generations of the experimental design (including 456 F2 pigs) were genotyped for 91 microsatellite markers covering all the autosomes. A total of 56 QTL were detected: 49 reached the chromosome-wide level (suggestive QTL with a maximal probability of 0.05) and seven were significant at the genome-wide level (with a probability varying from 6 3 10 24 to 3 3 10 23 ). Twenty suggestive QTL were identified for ultimate pH, colour measurements and WHC on chromosome (SSC) 5, 6, 7, 8, 9, 11, 13, 14, 15 and 17. For production traits, 33 QTL were detected on all autosomes except SSC6, 8 and 9. Seven of these QTL, located on SSC2, 3, 10, 13, 16 and 17, exceeded the genome-wide significance threshold. Finally, three QTL were identified for levels of stress hormones: a QTL for cortisol level on SSC7 in the cortisol-binding globulin gene region, a QTL for adrenaline level on SSC10 and a QTL for noradrenaline level on SSC13. Among all the detected QTL, seven are described for the first time: a QTL for ultimate pH measurement on SSC5, two QTL affecting birth weight on SSC2 and 10, two QTL for growth rate on SSC15 (during fattening) and 17 (during post-weaning) and two QTL affecting the adrenaline and noradrenaline levels. For each QTL, only one to five of the six F1 sires were found to be heterozygous. It means that all QTL are segregating in at least one of the founder populations used in this study. These results suggest that both meat quality and production traits can be improved in purebred Duroc and Large White pigs through markerassisted selection. It is of particular interest for meat quality traits, which are difficult to include in classical selection programmes.