ارزيابي چند شكلي ژن كاپا كازئين با استفاده از روش PCR-RFLP و ارتباط آن با صفات توليدي مهم گاوهاي شيري هلشتاين استان اصفهان

چكيده انگليسي :

Assessment of Kappa Casein Gene Polymorphism Using PCR RFLP and itsAssociation with Important Production Traits in Iranian Holstein Dairy Cows Khodaverdi Javansiah Bigdilo Javan ulduz 1983@gmail com Date of submission September 2011 Department of Animal Science Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi 1 HamidReza Rahmani Associate Professor supervisor 2 Mohammad Ali Edriss Professor supervisor AbstractNutrient compositions of Milk are suitable and perfect components among foods that is consumed by human everyday Bovine milk contains approximately 3 5 protein of which 80 are caseins and 20 are whey proteins Casein genes of cattle are located in the q31 33 region of chromosome 6 and they form a cluster of four closelylinked genes located in the following order s1 casein casein s2 casein and casein The entire cluster is 200kb in length The s1 casein casein and s2 casein genes are linked most closely whereas the casein gene CSN3 is at least 70 kb away from others Kappa casein represents about 12 of total casein in bovine milk Thisprotein consists of 169 amino acid residuals with a calculated molecular weight 19000 Dalton Two kappa caseinvariants denoted as A and B have been found in Holstein milk Alleles A and B of the CSN3 gene differ from eachother in two amino acid substitutions 136 Thr A Ile B and 148Asp A Ala B The nucleotide substitutions inthis positions leads to create or loss restriction enzyme recognition site and using this we can identify differentalleles of this gene Blood samples obtained from a random sampling of dairy Holstein cows maintained in fivefarms located in Isfahan province n 408 to investigate polymorphism of kappa casein gene Number of samplesvaried from 65 to 96 among herds DNA was extracted using salting out procedure The quality and quantity ofDNA determined by electrophoresis and spectophotometry The 633 bp fragment of this gene amplified usingspecific primers by PCR This fragment consists of a part of intron III 4 bp exon IV 516 bp and intron IV 113bp PCR product was detected by electrophoresis on 1 TAE agarose gel Amplified fragment digested usingHindIII restriction enzyme for 10 to 14 hours at 37 c The genotype frequency of AA AB and BB were 0 667 0 229 and 0 033 respectively Allele A of the casein gene occurred at a higher frequency than allele B Thefrequencies of alleles A and B alleles were 0 817 and 0 183 respectively The A allele in Herd 1 was more frequentthan other herds but the A allele in Herd 3 was lowest frequency The BB genotype in herd 4 had highest frequencywhereas this genotype in herd 1 and 2 wasn t observed All five herds were in Hardy Weinberg equilibrium TheShannon and Nei s index showed herd number 1 has lowest and herd number 3 has highest gene diversity among thestudied herds The polymorphism information content PIC was 0 254 indicate that this marker has medium powerto separate different genotypes In this study the association between kappa casein genotypes and productive andperformance traits was analyzed by MIXED procedure of SAS software The results showed significant associationsbetween the genotypes with fat and protein percentages and lactation period No significant association was foundbetween genotypes and adjusted 305 day milk pregnancy length conception rate and SCS P 0 05 Animalscarrying the AB genotype had higher fat and protein percentages and longer lactation period than AA animals P 0 05 It could be concluded that if the purpose of selection is increase of fat and protein percentage we coulddeserve selection using this condidate gene Key words kappa casein gene polymorphism Holstein cow Production Traits genotype

جوان سياه بيگديلو، خداويردي

ارزيابي چند شكلي ژن كاپا كازئين با استفاده از روش PCR-RFLP و ارتباط آن با صفات توليدي مهم گاوهاي شيري هلشتاين استان اصفهان

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