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IWMGQSG, December 8 – 11, 2003, Toulouse QUANTITATIVE TRAIT LOCI FOR PARASITE RESISTANCE Sonja Dominik CSIRO Livestock Industries Armidale.

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Presentation on theme: "IWMGQSG, December 8 – 11, 2003, Toulouse QUANTITATIVE TRAIT LOCI FOR PARASITE RESISTANCE Sonja Dominik CSIRO Livestock Industries Armidale."— Presentation transcript:

1 IWMGQSG, December 8 – 11, 2003, Toulouse QUANTITATIVE TRAIT LOCI FOR PARASITE RESISTANCE Sonja Dominik CSIRO Livestock Industries Armidale

2 IWMGQSG, December 8 – 11, 2003, Toulouse BONJOUR!!!

3 IWMGQSG, December 8 – 11, 2003, Toulouse KEY MESSAGES Parasite resistance is ….a prime trait to investigate on a molecular level ….a very complex trait ….difficult to collect phenotypes for ….evidently influenced by major genes

4 IWMGQSG, December 8 – 11, 2003, Toulouse INTRODUCTION Parasite resistance is a prime trait to investigate on a molecular level!

5 IWMGQSG, December 8 – 11, 2003, Toulouse ECONOMIC IMPACT Direct cost ~ AUS$ 50 Million = EURO 30 Million + Indirect Cost ~ AUS$ 250 Million = EURO 150 Million Total Cost ~ AUS$ 300 Million = EURO 180 Million

6 IWMGQSG, December 8 – 11, 2003, Toulouse GENETIC VARIATION Between breed variation

7 IWMGQSG, December 8 – 11, 2003, Toulouse GENETIC VARIATION Within-breed variation allows genetic progress

8 IWMGQSG, December 8 – 11, 2003, Toulouse THE TECHNOLOGY…

9 IWMGQSG, December 8 – 11, 2003, Toulouse PARASITE OF MAJOR IMPORTANCE Haemonchus contortus (Barbers pole) Trichostrongylus colubriformis / vitrinus (Black scour worm) Teladorsagia circumcincta (syn Ostertagia or Brown stomach worm)

10 IWMGQSG, December 8 – 11, 2003, Toulouse DIAGRAM OF IMMUNE RESPONSE EXPULSION OF WORMS Gut mucosa Th B-cells Clonal expansion Plasma cellsAB Clonal expansion Processing / Recognition Mesenteric lymph nodes Antigens Behnke et al Stemcells Mastcells Eosinophils Neutrophils Recruitment Bone marrow Th2 activation Cytokines IL-3, IL-4, IL-5,IL-6, IL-9, IL-10, IL13 Memory B-cells IgG,IgM,IgE Inflammatory mediators Plasma cells Goblet cells IgAIgG 1 IgE Mucus Peristalsis

11 IWMGQSG, December 8 – 11, 2003, Toulouse Some key component genes Large allelic variation Dominant Heritability 0.2 – 0.4 MHC genes responsible for some genetic variation between strains Interaction between MHC and non- MHC genes INSIGHTS FROM MOUSE EXPERIMENTS

12 IWMGQSG, December 8 – 11, 2003, Toulouse FEC TWC Serum antibody Circulating eosinophils Packed cell volume Plasma pepsinogen Dag score Faecal consistency score PHENOTYPIC INDICATORS Worm burden Physiological host response Clinical symptoms (Beh and Maddox 1996)

13 IWMGQSG, December 8 – 11, 2003, Toulouse QTL FOR PARASITE RESISTANCE TRAITS IN SHEEP Segregation analysis H. contortus –Evidence for two QTL based on FEC in ITT x Merino (Raadsma et al. 2002) –Evidence from segregation analysis for QTL based on FEC in Merino (Meszaros et al. 2001)

14 IWMGQSG, December 8 – 11, 2003, Toulouse 347 cM Chromosome 1 T.colubriformis EPCDV010 – ILSTS044 (Diez-Tascon et al. 2002) T. colubriformis McM130 – McM257 (Beh et al. 2001)

15 IWMGQSG, December 8 – 11, 2003, Toulouse Chromosome cM T. colubriformis TGLA67 – OarVH130 (Beh et al. 2001) Multiple species IFNG region (Paterson et al. 2002) Te. circumcincta IFNG region (Coltman et al. 2001)

16 IWMGQSG, December 8 – 11, 2003, Toulouse Chromosome cM T. colubriformis McM140 – McM257 (Beh et al. 2001)

17 IWMGQSG, December 8 – 11, 2003, Toulouse 89.6 cM Chromosome 20 Te. circumcincta DY locus (Buitkamp et al. 1996) H. contortus OarCP73 BM1815 DYMS1 (Janssen et al. 2002) Te. circumcincta MHC-DRB1 (Schwaiger et al. 1995)

18 IWMGQSG, December 8 – 11, 2003, Toulouse QTL FOR PARASITE RESISTANCE TRAITS IN SHEEP Summary –Evidence of QTL for parasite resistance –Difficult to compare studies – wide range of phenotypes –Most findings do not overlap, but IFNG is a very likely candidate

19 IWMGQSG, December 8 – 11, 2003, Toulouse CSIRO GENE MAPPING FLOCK HS Progeny 229 animals genotyped FS-1FS-4FS-5FS-6 FS-7FS-8 FS-2FS Total of 15 fullsib groups 172 animals genotyped ♀ ♂ ♂♀ ♀ ♀♀♀♀ ♀ Romney Grandsires Merino Granddams F1

20 IWMGQSG, December 8 – 11, 2003, Toulouse MATERIALS & METHODS Phenotypic data FEC 3, 4 and 5 FEC3, FEC4, FEC5 -> total FEC crFEC3, crFEC4, crFEC5 -> total crFEC 160 records Between 28% and 86% of animals infected

21 IWMGQSG, December 8 – 11, 2003, Toulouse MATERIALS & METHODS Protocol Check phenotypes for possible errors Check genotype data Test fixed effects Check residuals for normality QTL Express / Rqtl

22 IWMGQSG, December 8 – 11, 2003, Toulouse DISTRIBUTION OF RESIDUALS

23 IWMGQSG, December 8 – 11, 2003, Toulouse RESULTS crFECtotal FECtotal crFEC5 FEC5 crFEC4 FEC4 crFEC3 FEC3 HKNPMLHKNPML Chr. BChr. A LOD scores for parasite resistance traits

24 IWMGQSG, December 8 – 11, 2003, Toulouse KEY POINTS FROM CSIRO MAPPING FLOCK Some evidence for QTL for parasite resistance Data Analysis Extension of the CSIRO mapping flock will provide more data for closer investigation Binomial analysis as an alternative analysis approach

25 IWMGQSG, December 8 – 11, 2003, Toulouse KEY MESSAGES Parasite resistance is ….a prime trait to investigate on a molecular level ….a very complex trait ….difficult to measure ….evidently influenced by major genes

26 IWMGQSG, December 8 – 11, 2003, Toulouse THE FUTURE More work on the effects of data quality and analysis method on findings Combination of candidate gene approaches and mapping studies Comparative genomics plays an important role

27 IWMGQSG, December 8 – 11, 2003, Toulouse THANK YOU


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