Studies On Polymorphisms Of H-FABP And A-FABP Genes And Their Associations With IMF Trait In Pigs

Meat quality trait is an important economic character. A negative genetic correlation is found between meat quality and growth traits or carcass traits. There is antagonism between the meat production and meat quality. The improvement of lean meat percentage lows the IMF content of pork out of the best range, and the tender and flavo.' is also decreased. Thus meat is of poor quality. But it is difficult to improve both the quantity and quality of meat by the traditional breeding methods. Therefore, the major genes and QTL, affecting meat quality are studied. Candidate gene method is one of the approaches which are often used to study quantity trait in animals. At present, H-FABP and A-FABP genes are certain to be the major candidate genes affecting the IMF content in swine. In this tad>. DNA samples from 207 pigs including four imported breeds: Duroc. Hampshire, Landrace and Yorkshire and one native breed of China: Laiwu, were analyzed. H-FABP and A-FABP genes were studied by PCR-RFLP, and microsatellite, respectively. Meanwhile the microsatellite loci of A-FABP gene was cloned and sequenced. The effect of genetic variation of the two genes on IMF content was analyzed. The aim of this study was to determine the major genes affecting IMF deposition or the genetic markers linked with them tightly.The study of H-FABP gene in the five breeds by PCR-RFLPS showed one Hint" I -RFLP in 5'-upstream and one Haelll-RfLP and one Hinf I -RFLP in the second intron. The result was accorded with the previous reports. But the allele frequency of every locus was different significantly. The frequencies of H allele for Hinf I -RFLP in Laiwu, Duroc, Hamipire, Landrace, and Yorkshire, were 0.6087, 0.5227, 0.25, 0.8511 and 0.7273, respectively; the frequencies of B allele for Hinf I '-RFLP were 0.5937, 0.3478, 0.6000, 0.1153 and 0.3750, respectively; the frequencies of D for Haelll-RFLP were 0.8158, 0.6429. 0.9643, 0.2778 and 0.6522, respectively. The difference of genetic properties among the five breeds was also significant. In Hinf-RFLP. except Landrace that had lowpolymorphism(PIC<0.25), the others had intermediate polymorphism(0.250.5). but the other three breeds were of low polymorphism(PIC<0.25). In addition, the mutations of two bases was discovered. One was C ?T. the other was A-G. Allele B and C had these two mutations, nevertheless, allele D had C-*T only, allele A had no mutation.The effect of RFLPS for H-FABP gene on IMF content was analyzed by Least Square .Means. IMF content of the monoploid genotypes dd-hh-BB was the highest. For the homozygous genotypes. IMF content of genotype DD was the highest (5.0622%) and thai of genotype CC was next to DD; the LSM value of genotype CC was the highest and i; had the topmost effect.In summary, it is necessary to further explore genetic markers linked with major gene affecting IMF deposition by using more animals, applying family design, and combinin...