Texel
Suffolk
Charollais
Detection of differentially expressed genes in the M. longissimus thoracis et lumborum from full-sibling lambs divergent for fatness T Alam1*, V Campos1, J P Hanrahan2, P Allen3, T W J Keady2, M T Ryan1, R M Hamill3, T Sweeney1 (1) School of Veterinary Medicine, University College Dublin, Ireland (2) Teagasc Animal & Grassland Research and Innovation Centre, Athenry, Co. Galway, Ireland (3) Teagasc Food Research Centre, Ashtown, Dublin, Ireland *
[email protected]
Application Functional polymorphisms in genes identified as differentially expressed and associated with fatness will be useful for genomic selection for carcass and meat quality traits in breeding programmes.
Introduction One of the main factors affecting lamb-eating quality is fat content, which is positively correlated with juiciness, flavour, tenderness and overall acceptability. Long-term selective breeding for enhanced lean growth has reduced intramuscular fat levels with subsequent detrimental effects on eating (Hopkins et al., 2005).
Objective The aim of this study was to identify a panel of functional candidate genes associated with lipid metabolism that are differentially expressed in the M. longissimus thoracis et lumborum (LTL), using a divergent fullsibling model.
Materials and Methods
Result
• Sixty-four pairs of full-sibling lambs • Charollais (n = 20), Suffolk (n = 21) and Texel (n = 23) Experimental animal
7 pairs selected (divergent for fatness)
QPCR and selection of DEGs
*** High fatness
• The adjusted data (residual fat depth and residual fat score) were combined (Proc PRINCOMP; SAS 2012) to yield an index of withinlitter divergence for fatness • The most divergent pairs (n=7) of twin lambs were identified, each yielding 1 HIGH and 1 LOW lamb in the index for fatness
Low fatness
*** P < 0.001 ** P < 0.01 * P < 0.05
*** **
*
• QPCR was performed on a panel of 32 potential candidate genes. • The NRQ for the HIGH and LOW groups were compared (Proc GLM; SAS 2012) and 4 differentially expressed genes were identified
Panel of 32 potential candidate genes: ADIPOQ, ALDH2, CHRNE, DAD1, DGAT1, FABP3, FABP4, FAM134B, FASN, FOXO1, GHR, HMGA1, HSPA1A, IGF2, IGFBP3, LDLR, LIPE, LPL, MAP4K4, MMP1, MSTN, MYH7, MYOZ1, NEB, PGC1A, PLTP, PPARD, PRKAG3, SENP6, SOCS2, TCF12, TPI1, TRDN, ADIPOQ
FABP3 MMP1 MSTN LPL Figure 1. Mean NRQ values for genes with DE for fatness (vertical bars represent SEM)
Conclusion Four genes (FABP3, LPL, MMP1 and MSTN ) were differentially expressed between twin lambs divergent in fatness. Functional polymorphisms in the promoter region of these genes are currently being investigated. Reference: Hopkins DL, Hegarty RS, Farrell TC 2005. Aust. J. Exp. Agr, 45(5), 525–533.
Acknowledgements:
This work is funded by the BreedQuality project (11/SF/311), supported by The Irish Department of Food, Agriculture and the Marine (DAFM) under the National Development Plan 2007-2013
