Analyses Of Molecular Genetic Polymorphisms Of The H-FABP Gene And Their Associations With Intramuscular Fat Content In Pigs

Intramuscular fat content is an important meat quality trait in pig production. Previously, heart fatty acid-binding protein ( H-FABP) gene was studied as a candidate gene which having effects on intramuscular fat content (IMF%) . Five breeds, including mashen pig, Shanxi White pig, Large White pig, Landrace and Duroc, and four crossbred populations from Large White pig X Shanxi White pig(dashan pig), DurocXShanxi White pig(dushan pig), Large White pigXmashen pig (daben pig) and Duroc×mashen pig (duben pig), were used as experimental populations. PCR-RFLP and PCR-SSCP analyses were used to study genetic variations in the H-FABP gene. The associations between genetic markers and intramuscular fat content (IMF) were analyzed by using general linear model (GLM) .1. The genetic variation in 5' -upstream and in intron 2 of porcine H-FABP gene were detected by PCR-RFLP in the above populations. The results suggested: (1) at the Hinf I -RFLP site of the 5' -upstream, five breeds varied and mashen pig only had 2 genotypes( Hh vs hh). For crossbred populations, dushan pigs were homozygote HH while daben pig only had 2 genotypes (HH vs Hh) . (2) at the HinfI -RFLP site of the second intron, all the populations varied while mashen pig only had 2 genotypes (BB vs Bb) . (3) at the HaeIII-RFLP site of the second intron, all tested mashen pigs were homozygote DD while other populations varied, daben pig and duben pig only had 2 genotypes (DD vs Dd) . (4) allele D, h and B in mashen pigs were superior genes, and their frequencies were 1.0000, 0.9727 and 0.9667, respectively. (5) Shanxi White pigs were proved to be polymorphic at three restriction sites , and allele frequencies of H, D and B were 0.7595, 0.2476 and 0.2423, respectively.2. According to the related sequences of porcine H-FABP gene released on GenBank, specific primers P3 ~P8 were designed to amplify fragments from porcine H-FABP gene. Only one PCR-SSCP locus, designated as P4-SSCP. was discovered and had two alleles, designated A and B. Sequence analysis revealed P4-SSCP locus was generated because of C—T transition.3. Primer P9 was designed to amplify the 1350 bp fragment of the third intron of porcine H-FABP gene. Sequence of intron 3 was submitted to GenBank and GenBank accession NO is DQ 002993. Primer P10 was designed to amplify a 255 bp fragment in porcine H-FABP gene intron 3 based on the result of sequence analysis. P10-SSCP was found to have two alleles, designated A and B. Sequence analysis revealed P10-SSCP locus was caused by a A-G transition.