BACKGROUND: Major histocompatibility complex (MHC) encodes for highly variable molecules, most of which are responsible for foreign antigen recognition and activation of immune responses in the host. LEI0258 microsatellite, located in the poultry MHC region, is a suitable genetic marker for determining MHC haplotypes and genetic diversity in poultry.OBJECTIVES: Considering the fact that there is no report on the frequency and types of MHC alleles and population genetic analysis in Ross 308 poultry in Iran, the present study aimed to investigate the diversity of MHC haplotypes of Ross 308 broilers by LEI0258 microsatellite.METHODS: A total of 216 blood samples were collected from two productive herds of Ross 308 broilers. After extracting DNA of the blood samples and amplifying LEI0258 microsatellite alleles, genotyping of MHC haplotypes was performed using agarose gel electrophoresis and fragment analysis techniques.RESULTS: A total of seven alleles and 21 genotypes were identified for LEI0258 microsatellite in these two groups. the highest and the lowest frequencies belonged respectively to allele 385 bp (42.86 %) and allele 300 bp (4.33 %). Heterozygous 207/385 was found to be the dominant genotype in both populations. According to the similarity matrix analysis, there was an 84.56 % similarity between the two groups.CONCLUSIONS: The results obtained in this study revealed a high level of heterozygosity (85.71 % and 91.35 %) and deviation from Hardy–Weinberg equilibrium (P<0.0001) in these two Ross populations. Ross 308 broiler chickens had lower allelic diversity and higher genetic similarity compared to the native ones. These findings provided additional information on the use of MHC as a candidate gene marker in genetic improvement and resource conservation in broiler populations.

BACKGROUND: Major histocompatibility complex (MHC) comprises a group of genes, which plays a central role in immune response. The exon 2 of BuLA-DRB3 is part of the MHC class II in buffalo that highly polymorphic, found to be associated with resistance/susceptibility to infections and also with production parameters. OBJECTIVES: The purpose of the present study is to identify BuLA-DRB3 polymorphism in Khuzestan buffaloes and compare this population with other Iranian and world buffalo populations. METHODS: Blood samples were taken from 136 unrelated Khuzestan river buffaloes. After DNA extraction, second exon of BuLA-DRB3 was amplified by the seminested PCR method. Then, the fragments produced by amplifying second exon were cut by RsaI restriction enzyme according to van Eijik method. In the following, allelic frequencies, genotype frequencies, expected and observed homozygosty and heterozygosity were calculated. RESULTS: In restriction fragment analysis 13 and 24 different allelic and genotype patterns were identified for RsaI restriction enzyme, respectively. 10 out of 13 alleles were previously reported. The most frequent genotype was oo)0.1691) and then followed by hh (0.1544) ,ll(0.1103), lw (0.0955), lh (0,0808), ha (0.0661) and lo (0.0514). Also four most frequent alleles were o (0.2721), h (0.2316),l (0.2316)and w (0.1176), respectively. These seven genotypes and four alleles form 72.76% and74.29% overall genotype and allele frequency of population.  In addition, estimation of heterozygosity/homozygosty and deviation from Hardy-Weinberg equilibriumofcorresponding population revealed observed homozygosty is more than heterozygosity and departure of population from Hardy-Weinberg equilibrium. CONCLUSIONS: The results indicated that exon 2 of the BuLA-DRB3 gene is highly polymorphic among Khuzestan buffaloes and although, there is differences between buffalo’s genetic polymorphism of distinct world regions, Khuzestan buffaloes’ population is similar to Egyptian buffaloes’ population.

BACKGROUND: Chicken major histocompatibility complex region (MHC) is important in the productive traits, immune responses, resistance to infectious diseases and phylogenetic relationships. OBJECTIVES: This study was investigated for single nucleotide polymorphisms of MHC region related to the immune system in commercial broiler and layer chickens. METHODS: One hundred blood samples were taken from commercial broiler and layer chickens and genomic DNA was extracted by salting out method. The allelic polymorphisms were investigated in B-L, B-F and B-G loci using PCR-RFLP and MspI enzyme. RESULTS: For two commercial broiler and laying populations, in the 374 bp locus of B-L, only BB genotype was detected but in the 1048 bp locus of B-F, two genotypes of CG and GG were identified in broiler chickens. The C allele contained four bands of 515, 410, 75 and 47 bp, and the G allele with five bands of 410, 302, 213, 75 and 47 bp. In B-G (401 bp) locus, three genotypes of MM, MN and NN and two alleles of M with one band (401 bp) and N with two bands (350 and 51 bp) were identified. In total populations, the Shannon information index was calculated to be 0.45 and 0.73 in markers loci of B-F and B-G, and the fixation index values were -0.20 and 0.34, respectively. The highest observed heterozygosity index for B-F and B-G loci was 0.34 and 0.23, respectively. CONCLUSIONS: Considering the confirmation of the presence of polymorphism in two loci of the B-F (in commercial broiler population) and B-G (in commercial broiler and layer populations), these sites can be used as genetic marker in breeding programs to increase resistance to diseases.

A total of 142 chicken blood samples were collected and a specific primer set was used to amplify a fragment of growth hormone locus using PCR. PCR products were digested with SacI and MspI restriction endonucleases. The amplified fragment digested with SacI enzyme revealed two “+” (wild type) and “-” (normal type) alleles with the frequency of 0.898 and 0.102, respectively. The amplified fragment digested with MspI enzyme revealed three A, B and C alleles with the frequency of 0.599, 0.102, and 0.299, respectively. Frequencies of +/+, +/- and -/- were 0.817, 0.162, and 0.021, respectively, and those of AA, AB, AC, BB, BC, and CC were 0.338, 0.113, 0.409, 0.007, 0.070, and 0.063, respectively, in the studied population. The results of 2 and likelihood ratio tests showed that this population was at Hardy-Weinberg equilibrium with respect to the marker locus. Marker-trait association analysis revealed statistically significant differences between “SacI-RFLP” genotypes for egg production and rate of laying eggs. The relationship between the molecular marker and these traits can be useful to improve the chicken breeding programmes.

Encephalomyocarditis virus (EMCV) belongs to the genus Cardiovirus within the family Picornaviridae. EMCV has been recognized either as a cause of mortality in young pigs, due to acute myocarditis, or of reproductive failure in sows. An EMCV K3 strain was isolated from the heart and brain in a mummified and aborted swine fetus in 1989. For the molecular characterization of the poly(C)-tract of EMCV Korean isolates, K3 strain, viral RNA was extracted and digested with RNase T1, and analyzed the length of the poly(C)-tract by polyacrylamide gel electrophoresis. The poly(C) regions also were amplified by RT-PCR and sequenced. The present study shows that K3 strain of EMCV had a short polymorphic poly(C) tracts (5 to 30 C's) with sequences consisting of C∧9, C∧10, C∧13, C∧14, C∧16, C∧20, CUC∧11, C∧8UCUC₃UC∧10, C∧9UCUC₃UC∧10, C∧10UCUC₃UC∧10, etc. These polymorphism of poly(C)-tracts of EMCV K3 strain implies the historical information of in vivo and/or in vitro passage.

Genomic DNA polymorphisms obtained by restriction fragment-length polymorphism from healthy horses and horses with hereditary multiple exostoses were analyzed. These DNA were digested by 12 restriction enzymes and were hybridized against 6 isotopically labeled oncogene probes. Hybridization was not detected with the viral oncogene, v-ras, which indicated this oncogene was absent in the equine genome. Oncogenes (c-raf-1, c-fes, c-myb, c-myc, and c-sis) were present and had similar hybridization patterns and signal intensities in DNA from healthy horses and horses with hereditary multiple exostoses. Unique and distinct restriction fragment-length polymorphisms were detected with the c-raf-1 probe only in BamHI- and PstI-digested equine DNA.

The duration of the incubation period for scrapie, a fatal transmissible neurodegenerative disorder of sheep and goats, is mainly determined by the Sip gene, which has 2 alleles (sA-susceptible and pA-resistant). A diagnostic test is not available to detect scrapie in live animals. We analyzed genomic DNA extracted from frozen sheep brains collected from Cheviot sheep of the United States that had been inoculated with the SSBP/1 scrapie inoculum. Digestion of the DNA with EcoRI or HindIII followed by the addition of a scrapie-associated fibril protein (PrP)-specific marker probe, yielded fragments of 6.8 (e1) and 4.0 (e3) kb, or 5.0 (h1) and 3.4 (h2) kb, respectively. Fragments e1 and h2 were associated with the histopathologic diagnosis of scrapie, and fragments e3 and h1 were associated with survival. A valine/alanine polymorphism within the PrP coding region that resulted in a BspHI site was further used to determine the genotype of these Cheviot sheep. Digestion of polymerase chain reaction fragments with BspHI resulted in an undigested fragment b- (0.840 kb), digested fragments b+ (0.460 and 0.380 kb), or both types of fragments. Survival time of b+/b+ homozygous sheep was significantly (P < 0.01) shorter (218 +/- 26.0 days) than survival time for b-/b- sheep (> 700 days after inoculation). Results indicated that b+ and b- are markers for the Sip sA and pA alleles, respectively. The intermediate duration of the incubation period for heterozygous sheep (b+/b-; 342.9 +/- 25.3 days) indicated that the Sip sA allele is expressed codominantly to the Sip pA allele.

The Kedah-Kelantan cattle (KK) is an indigenous cattle breed and is mainly kept for meat production in Malaysia. Due to lack of information about polymorphism of growth traits in these cattle, Insulin-like Growth Factor 1 (IGF-1) was chosen to be the candidate gene in this preliminary study. The aim of this study is to investigate the polymorphism of IGF-1 gene in KK and to show that the PCR-RFLP technique can be used as a basis for use as molecular markers in cattle. A total of 46 KK blood samples were collected for DNA extraction performed using a commercial kit. The exon 1 of IGF-1 gene was amplified to produce a 249 bp fragment. The amplified fragments were digested with Eco105I restriction endonuclease and then subjected to electrophoretic separation in Fluorosafe stained 2.5 % agarose gel. The result revealed two alleles, A and B. Threegenotypes were observed: AA, AB and BB. Frequencies were 0.07, 0.13 and 0.80 for AA, AB and BB, respectively. This gives frequencies of 0.13 and 0.87 for A and B alleles. It is concluded that the population is in Hardy-Weinberg disequilibrium (p<0.05). It is possible that this gene has been exposed to selection.