Polymorphisms In Myod Gene Family And Their Associations With Meat Quality Traits In Chinese Indigenous Cattles

Beef is the culinary name for meat from bovines, especially domestic cattle. Beef can beharvested from cows, bulls, heifers or steers. It is one of the principal meats used in thecuisine of the Middle East (including Pakistan and Afghanistan), Australia, Argentina, Brazil,Europe and the United States, and is important in Africa, parts of East Asia. Beef is the thirdmost widely consumed meat in the world, accounting for about25%of meat productionworldwide, after pork and poultry at38%and30%respectively. In absolute numbers, theUnited States, Brazil, and the People's Republic of China are the world's three largestconsumers of beef. On a per capita basis in2009, Argentines ate the most beef at64.6kg perperson; people in the US ate40.2kg, while those in the EU ate16.9kg. The world's largestexporters of beef are Brazil, Australia, and the United States.In recent years, with the improvement of social development and people's livingstandards, dietary changes in the structure, not only to an increase in demand for beef, beefquality have further requirements. At present, the beef quality is low is considered to be oneof the main reasons restricting the development of China's Beef Industry. So it is veryimportant for us to enhance the production and meat quality traits in our local breeds by theuse of modern molecular biological techniques, such as DNA molecular markers.Myogenic determination (MyoD) family genes encode for skeletal muscle-specifictranscription factors with highly conserved basic helix-loop-helix domain and these are thekey genes for meat quality and production traits and are thereafter conceived as candidategenes for meat quality traits in farm animals. In this research, PCR-SSCP technology wasused to determine the single nucleotide polymorphism (SNP) in four MyoD family genes(MyF3, MyF4, MyF5and MyF6) and their associations with meat quality traits in Chineseindigenous cattle.The breeds used in this research includes Jia-xian red (JXR), Luxi (LX),Nan-yang (NY), Qinchuan (QC), Xia-Nan (XN) and Xuelong (XL) cattle. Primarily, the SNPswere detected by PCR and sequencing, and they were confirmed by single strandedconfirmation polymorphism (SSCP) method. Six SNPs including MyF3(166C>G),MyF4(959A>G), MyF5(1553A>C and1142A>G) and MyF6(131T>G and 232A>C), were screened in these genes.The g.1142A>G and g.131T>G SNP genotypes ofMy5F5and MyF6genes, respectively, had significant associations with intramuscular fat (IF),rib area (RA), water holding capacity, loin eye area (LEA) and Meat tenderness (MT), inChinese cattle (P<0.05). In addition, g.959A>G polymorphism in MyoG gene has shownhighly significance associations for meat tenderness and water holding capacity.Whereas, lackof an association between a single nucleotide polymorphism in the bovine MyF3(166C>G)gene and meat quality traits were observed. Remarkable differences in allele and genotypicand frequencies were observed for the6selected SNPs among6different cattle breeds. Basedon the χ2test, without few exceptions, the genotype distributions of all the SNPs among mostof the cattle breeds were not in Hardy-Weinberg equilibrium (P <0.05) and showed moderatediversity (0.25<polymorphism information content <0.5). Our result suggests that A1142G,A959G and T141G SNPs have potential effects on meat quality traits in the above mentionedcattle populations and are therefore useful for marker-assisted selection. Furthermore, it isalso inferred that the results mentioned here will provide selective information for improvingmeat quality traits in cattle.