Seven genes (BF, EGF, ESR, FSHB, H2AFZ, LEP and PRLP) were studied as candidate gene influencing eleven reproduction traits (interval between litters (IBL), percent of litter (PL), number of litters (NL), number of piglets born dead (NBD), number of piglet born alive (NBA), total number born (TNB), mean of born alive (MBA), mean of born dead (MBD), mean of born total (MBT), mean of piglets at 21 days of age (M21D) and growth rate (GR) in three pig breeds (Hungarian Large White (HLW), Duroc and Pietrain) by PCR-RFLP. Based on the observed vs. expected genotypes frequencies populations across loci were in Hardy-Weinberg equilibrium (P>0.05). In case HLW breed ESR and FSHβ genes were in disequilibrium. Association study suggested that only EGF gene showed significant influence on the trait NBA and TNB. The AA genotype are preferable for sows, associated with higher NBA and TNB. The longest IBL, and the highest NL is associated with AB and AA genotype of EGF gene. IBL is significantly shorter in case of pigs with AB and AA alleles than BB alleles of PRLP genes. Selection for these SNPs could improve the reproductivity in the studied breeds.
The quality of RNA is crucial in gene expression experiments. RNA degradation interferes in the measurement of gene expression, and in this context, microRNA quantification can lead to an incorrect estimation. In the present study, two different RNA isolation methods were used to perform microRNA microarray analysis on porcine brain tissue. One method is a phenol-guanidine isothiocyanate-based procedure that permits isolation of total RNA. The second method, miRVana™ microRNA isolation, is column based and recovers the small RNA fraction alone. We found that microarray analyses give different results that depend on the RNA fraction used, in particular because some microRNAs appear very sensitive to the RNA isolation method. We conclude that precautions need to be taken when comparing microarray studies based on RNA isolated with different methods.