پديد آورنده :
دادار، محسن
عنوان :
بررسي ساختار ژنتيكي و انتخاب بهترين سهم ژنتيكي در گاوهاي هلشتاين ايران
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي
صفحه شمار :
يازده،76ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
محمدعلي ادريس، سعيد انصاري مهياري
توصيفگر ها :
تنوع ژنتيكي , هم خوني , شجره
تاريخ نمايه سازي :
3/12/93
استاد داور :
عباس پاكدل، سعيد اسماعيل خانيان، محمود وطنخواه
كد ايرانداك :
ID718 دكتري
چكيده انگليسي :
Genetic Structure and Optimal Genetic Contribution Selection in Iranian Holstein Cattle M Dadar 1 S Ansari Mahyari 1 M Rokouie 2 and M A Eddris 11 Department of Animal Science College of agriculture Isfahan University of Technology Isfahan 84156 83111 Iran 2 Department of Animal Science University of Zabol Zabol IranAbstract The accumulation of inbreeding and the loss of genetic diversity is a potentialproblem in the Holstein dairy cattle The goal of this study was to estimate inbreedinglevels and other measures of genetic diversity using pedigree information from IranianHolstein cattle Edited pedigree included 1 048 572 animals The average number ofdiscrete generation equivalents and pedigree completeness index reached 13 4 and 90 respectively The rate of inbreeding was 0 3 per year Effective number of founders founder genomes non founders and ancestors of animals born between 2003 and 2011were 503 15 6 16 1 and 25 7 respectively It was proved that the unequal foundercontributions as well as bottlenecks and genetic drift were important reasons for the loss ofgenetic diversity in the population The top 10 ancestors with the highest marginal geneticcontributions to animals born between 2003 and 2011 and with the highest contributions toinbreeding were 48 20 and 63 94 respectively Analyses revealed that the mostimportant cause of genetic diversity loss was genetic drift accumulated over non foundergenerations which occurred due to small effective population size Therefore it seems thatmanaging selection and mating decisions are controlling future coancestry and inbreeding which would lead to better handling of the effective population size Keywords inbreeding genetic diversity Iranian Holstein pedigreeINTRODUCTIONThe study of population structure by pedigree analysis is referred as a useful measure toidentify important circumstances that affect the genetic history of a population Valera etal 2005 The intensive use of a small number of superior individuals which are oftenselected using procedures such as BLUP may reduce the genetic diversity of the underinvestigation populations The reduction in genetic diversity and its effects have beenextensively studied in different species particularly in beef cattle Burrow 1998 SantanaJr et al 2010 One of the most relevant effects resulting from reduced genetic diversity isinbreeding depression which compromises the performance of domestic animals Croquetet al 2007 Gonz lez Recio et al 2007 Panetto et al 2010 The rate of inbreeding is acommon means to monitor changes of genetic diversity through its transformation to theeffective size of population However this method is very sensitive to incomplete pedigreeinformation Another complementary approach is the analysis of the probabilities of geneorigin In this approach the genetic diversity is evaluated using parameters such aseffective number of founders and ancestors from cattle to treated Honda et al 2004 Thegoal of this study was to assess the past and current inbreeding levels and genetic diversity
استاد راهنما :
محمدعلي ادريس، سعيد انصاري مهياري
استاد داور :
عباس پاكدل، سعيد اسماعيل خانيان، محمود وطنخواه
