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Ghyslaine ppt

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Gene detection for milk protein composition in dairy cattle

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Ghyslaine ppt

  1. 1. Animal Breeding & Genomics Centre Gene detection for milk protein composition in dairy cattle Ghyslaine Schopen Thursday 12th March 2009
  2. 2. Animal Breeding & Genomics Centre Milk Genomics Initiative Aim: To identify opportunities to use genetic variation to improve milk quality characteristics  Milk quality:  Milk-fat composition  Milk-protein composition  Improve:  Technological efficiency (production of cheese, butter)  Innovative dairy products (e.g. promoting human health)
  3. 3. Animal Breeding & Genomics Centre Milk composition  Cow milk contains a unique source of bio-active components and nutrient, among which proteins  Six major milk proteins:  Caseins: αS1-casein, αS2-casein, β-casein and к-casein  Whey proteins: α-lactalbumin and β-lactoglobulin  Milk protein composition is important for the dairy industry:  Caseins are important for the cheese production
  4. 4. Animal Breeding & Genomics Centre Heritabilities for milk protein composition  Ranged from 0.25 for β-casein to 0.80 for β-lactoglobulin Schopen et al 2009 Journal of Dairy Science  Genes contribute to the genetic variation, however, it is not known which genes cause the genetic variation
  5. 5. Animal Breeding & Genomics Centre Aim To detect DNA regions on the cattle genome which have an effect on a quantitative trait
  6. 6. Animal Breeding & Genomics Centre Resource population 873 cows 50 bulls 5 bulls 848 cows
  7. 7. Animal Breeding & Genomics Centre Material & Methods  Milk sample  Capillary zone electrophoresis  Blood sample  DNA analyses • 1912 • 398 • Pedigree • 1 • Winter • 1 Minutes -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20 22 AU 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 AU 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 BSA56141 BSA114802 34243 a-lac943014 b-Lg-B2130515b-Lg-A1505886 1800076577877559 1163910 1373411 2897212 4386713 a-Cas-S2143209146167315 12240316 17162117 22288018 a-Cas-S1129719819 3363020 3980421 a-Cas-S053015322 34383233821324 k-Cas25819125 5743226 b-Cas-B5112327 10199528 b-Cas-A1109282729 865930 b-Cas-A2107159931 13083832 747633 1154334 1176735 2395336 3382437 3112738 1297539 212440 3170341 950742 2134343 2924844 2757745 PDA- 214nm 11891 Name Area Pk #
  8. 8. Animal Breeding & Genomics Centre Detection of DNA regions  Using 1341 Single Nucleotide Polymorphisms (SNPs) as genetic markers Ind 1 CACCGCGCCT GGTCCC G TTT TGGCTATTCT CACCGCGCCT GGTCCC G TTT TGGCTATTCT Ind 2 CACCGCGCCT GGTCCC A TTT TGGCTATTCT CACCGCGCCT GGTCCC A TTT TGGCTATTCT  Genetic markers can be used to reconstruct the inheritance from parents to offspring
  9. 9. Animal Breeding & Genomics Centre
  10. 10. Animal Breeding & Genomics Centre Variation between cows Trait Mean CV( % ) αs1 -Casein 33.62 5 αs2 -Casein 10.38 14 -Caseinβ 27.17 6 -Caseinк 4.03 14 -Lactoglobulinβ 8.35 14 -Lactalbuminα 2.44 13 Caseinindex 87.45 2 Protein % 3.51 9 β-lactoglobulin Numberofobservations % total protein Caseinindex = (αs1-Casein + αs2-Casein +β-Casein + к-Casein) / (αs1-Casein + αs2-Casein +β- Casein + к-Casein + β-Lactoglobulin + α-Lactalbumin) * 100 Schopen et al. (2009) Journal of Diary Science
  11. 11. Animal Breeding & Genomics Centre Detected DNA regions on the genome  Significant regions (Pgenome< 0.05) at chromosome 1, 3, 5, 6, 9, 10, 11, 14, 15 en 17  Chromosome 6: region affected all four casein fractions  Chromosome 11: region affected β-lactoglobulin fraction
  12. 12. Animal Breeding & Genomics Centre Variance explained by DNA regions Chromosome Trait VQTL (%) 6 αS1 -casein 6.8 6 αS2 -casein 6.7 6 -caseinβ 3.6 6 -caseinк 7.9 11 -lactoglobulinβ 28.3
  13. 13. Animal Breeding & Genomics Centre Detected DNA region on chromosome 6 and 11 β-casein 0 1 2 3 4 5 0 20 40 60 80 100 120 cM Test-statistics к-casein 0 2 4 6 8 10 12 14 0 20 40 60 80 100 120 cM Test-statistics β-lactoglobulin 0 10 20 30 40 50 60 70 0 20 40 60 80 100 120 cM Test-statistics
  14. 14. Animal Breeding & Genomics Centre Detection of DNA regions  Correct for known candidate genes  e.g. β-casein, к-casein and β-lactoglobulin
  15. 15. Animal Breeding & Genomics Centre β -lactoglobulin 0 20 40 60 80 100 120 140 160 180 4.0% 4.8% 5.6% 6.4% 7.2% 8.0% 8.8% 9.6% 10.4% 11.2% 12.0% 12.8% % of total protein Numberofobservations
  16. 16. Animal Breeding & Genomics Centre β -lactoglobulin 0 20 40 60 80 100 120 140 160 180 4.0% 4.8% 5.6% 6.4% 7.2% 8.0% 8.8% 9.6% 10.4% 11.2% 12.0% 12.8% % of total protein Numberofobservations Total AA
  17. 17. Animal Breeding & Genomics Centre β -lactoglobulin 0 20 40 60 80 100 120 140 160 180 4.0% 4.8% 5.6% 6.4% 7.2% 8.0% 8.8% 9.6% 10.4% 11.2% 12.0% 12.8% % of total protein Numberofobservations Total AB
  18. 18. Animal Breeding & Genomics Centre β -lactoglobulin 0 20 40 60 80 100 120 140 160 180 4.0% 4.8% 5.6% 6.4% 7.2% 8.0% 8.8% 9.6% 10.4% 11.2% 12.0% 12.8% % of total protein Numberofobservations Total BB
  19. 19. Animal Breeding & Genomics Centre β -lactoglobulin 0 20 40 60 80 100 120 140 160 4.0% 4.8% 5.6% 6.4% 7.2% 8.0% 8.8% 9.6% 10.4% 11.2% 12.0% 12.8% % of total protein Numberofobservations BB: 6.58% AB: 8.16% AA: 9.52%
  20. 20. Animal Breeding & Genomics Centre Detected region on chromosome 11 β-LG β-lactoglobulin 0 10 20 30 40 50 60 70 0 20 40 60 80 100 120 cM Teststatistic β-LG
  21. 21. Animal Breeding & Genomics Centre Detected DNA region on chromosome 6 β-casein 0 1 2 3 4 5 0 20 40 60 80 100 120 cM Test-statistics к-casein 0 2 4 6 8 10 12 14 0 20 40 60 80 100 120 cM Test-statistics Casein Casein
  22. 22. Animal Breeding & Genomics Centre Conclusion  Detected DNA region on chromosome 6 and 11 which affected the milk protein composition  The DNA region on chromosome 6 affected all four casein fractions and was partially explained by the genetic variants in the casein genes  The DNA region on chrosomsome 11 affected β- lactoglobulin fraction and was partially explained by the genetic variant A and B in β-lactoglobulin
  23. 23. Animal Breeding & Genomics Centre Opportunities for genetic selection Cheese production (high casein%) Health Promoting (low fat %)
  24. 24. Animal Breeding & Genomics Centre Acknowledgements  Farmers  Partners:  Milk Genomics Team  www.milkgenomics.nl
  25. 25. Animal Breeding & Genomics Centre Thank You for your attention! With breeding it is possible to change the milk protein composition!!

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