Effect of scd gene on milk production

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1. University of Debrecen Centre for Agricultural and Applied Economics Science Faculty of Agricultural and Food Sciences and Environmental Management Effect of…
  • 1. University of Debrecen Centre for Agricultural and Applied Economics Science Faculty of Agricultural and Food Sciences and Environmental Management Effect of Stearoyl-COA desaturase genepolymorphism on milk production traits of Hungarian Holstein Friesian cows By : Tegegn Gudeta, Jaleta (MSc thesis) Debrecen , Hungary, May 2012
  • 2. IntroductionMarker Assisted selection in modern dairyNumber of studies conducted in large scale on candidate genes in dairy breedingSCD is hypothesiszed candidate gene  It catalyze Cis∆-9 desaturation  Mapped to chromosome 26 in bovine  SCD 1 and SCD5  Associated with milk fatty acid compositionStudies of SCD gene not conducted in HHF
  • 3. Objectives of the studyTo estimating allele and genotype frequencies of SCD gene polymorphism(878 C/T)To determining the effect of SCD gene polymorphism on cows milk production traits
  • 4. Materials and Methods1) Animals and Milk data Hair root samples (8-10) were collected from 277 HHF in Tedej Dairy Farm located 15 km north of Debrecen One lactation milk record data were collected for 277 HHF cows-305 day average milk yield (kg), fat yield (kg), fat percentage(%), protein yield (kg), protein percentage (%) and SCC (10,000 cell/ml)
  • 5. 2) Study Methods Molecular Laboratory of UD DNA isolation from Hair root  3-5 hair root+ 100 µL Lysis buffer+1.5 ProteinK  Water bath for 60 min at 60 0c , for 20 min at 95 oc water bath, stored at -20 oc Spectrophotometrical Analysis-Nanodrop Spectrophotometer RT-PCR 7300
  • 6. 3) DNA Amplification and Sequencing 7300 RT-PCR machine (Applied Biosystem) Reaction mix(10µL): 1µl DNA, 5µl 1xTaqMan MasterMix (PN 4371355, USA), 0.25µl 1xSNP probe and 3.75µl dH2O. TaqMan probe sequence: The fluorescent probe VIC: ACTTACCCACAGCTCC The fluorescent probe FAM: TTACCCGCAGCTCC SCD Primers (625µl 40x mix, Warington, UK, WA37PB): Forward Primer: CCCCGAGAGAATATTCTGGTTTCC Reverse primer : CCACTAGACGTGGTCTTGCT
  • 7.  Amplification and Sequencing protocol  Initial steps: Activation at 950C for 10 minutes (AmpliTaq Gold DNA polymerase), Melting for 15 sec at 920C, Annealing/Extension at 600C for 1 minute (40 cycles). The SNP 878 C/T was used in this study and the nucleotide substitution was identified according to Tanguichi et al., (2004).
  • 8. 4.) Data Analysisa)Descriptive Statistics using R software (Version: R- 2.14.2)b)Hardy-Weinberg Equationc) Analysis of Variance (ANOVA) using R software (Version: R-2.14.2)
  • 9. Results and Discussion1. Genotypes and Allele Frequencies of SCD gene Polymorphisms  Amplification curve for CC(left) and CT(right) genotypes
  • 10. Result of amplification curve for TT genotype (Green line)
  • 11. Allelic discrimination of SCD genotypes (Blue-CC, Green-CT, and Red-TT)
  • 12. Genotype and allele frequencyy of the SCD gene in the investigated Hungarian Holsteins cow population No of Animals (Genotype SCD P value X2 Frequencies in %) Allele % CC CT TT 0.04695 3.947Observed 94(34) 148(53) 35(13) C(0.61)Expected 102(37) 132(48) 43(15) T(0.39)
  • 13. 2. Effects of SCD Genotypes on Recorded Milk Production Traits Parameter Genotype CC CT TT P value Fat (%) 3.76±0.41 3.8±0.43 3.7±0.38 0.2272 Protein (%) 3.22±0.178 3.22±0.178 3.23±0.14 0.998 SCC(X103 cell/ml) 136±106.4 116±70.2 119±72.7 0.2264 305 MY (kg) 8277.5±1301 8468.5±1542 8463.4±1294 0.5805 305 FY (kg) 310.6±52.4 321.9±55.2 313±50.6 0.2505 305 PY (kg) 266.1±38.5 272.1±45.8 272.3±36.2 0.5315Mean and standard deviation of milk production traits and its association withSCD genotypes.
  • 14. Conclussions Higher C allele(0.61) frequency and lower T allele (0.39) frequency was reported in this study The SCD genotypes frequency in HHF herds under this study were not in Hardy-Weinberg equilibrium, the possible reason for this result may be small numbers of animals included in this study and indicating the herds were not in a random mating system SCD-878 C/T locus cannot be considered as candidate gene in milk production traits Further studies will be necessary on large number of animals to confirm the current result
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