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Stearoyl-CoA desaturase (SCD) enzyme plays an important role in the metabolism of the lipids, thus the goal of this study was to investigate the influence of canola and soybean oilseeds on gene expression of SCD in adipose tissue, composition and yield of milk, fatty acid profile in Iranian Holstein cattle. Animals (n=20) were randomly selected to test experimental diets. Fatty acid composition was determined. After isolation of total RNA, cDNA was synthesized. Reverse transcription polymerase chain reaction (RT-PCR) was used to amplify SCD and GAPDH. For analyzing the real-time PCR results, LinRegPCR, REST and SPSS softwares was employed. The animals fed canola seed in comparison animals fed soybean seed showed higher gene expression. The milk production, fat percentage, 4% fat corrected milk, body condition score and milk urea nitrogen showed a significant difference between two groups. The amount of a number of fatty acids extracted from adipose tissue including C18:3t, C18:0 and C16:1 in animals fed two different diets was variable and their amount was significantly different. SCD gene expression was not significantly different between animals fed two diets (canola and soybean). This may be due to the similarity of the fatty acid composition of the two compounds and their nutrient balance. Since canola seed are higher in fat and protein than soybean seed, it can be a good substitute for soybean seed in the diet of dairy cows. In addition, canola seed, with the effect of nutrition on the composition of milk fatty acids can be used to improve milk. [ABSTRACT FROM AUTHOR]

The purpose of the research was to examine the behaviour of five hundred forty-two dairy cows in the 2 × 16 DeLaval parallel milking parlour. During ten milking sessions the consistency of the entrance order in the milking parlour was investigated, in particular group preference, side preference and standing position during milking and relationships of these behavioural elements with milk production and type of nervous activity (NA) of cows. The highest repeatability was characteristic of group preference (repeatability coefficient 0.47, p<0.001), lower repeatability was for side preference and standing position (0.17, p<0.001 and 0.09, p<0.05). Young cows preferred generally to be milked in the first group (average lactation number 1.7), they had lower milk yield compared with the average milk yield in the herd (305-d milk yield-7552 kg) and reactive type of NA. The third group for milking was preferable for older cows (2,3lactations) with higher milk yield (7827 kg) and inert type of NA. It has been established that 8-12% of cows consistently chose the right or left side in the milking parlour, 42% of cows did not show any side preference. There have not been found significant differences in age and milk production of cows depending on the side preference and standing position in the milking parlour. Using the own methodology, that based on the consistency of group preference and standing position in the milking parlour, cows were divided into three types of NA: reactive, balanced and inert. In the studied herd, reactive type of NA, balanced and inert contained 34%, 29% and 37% of cows, respectively. In cows of inert type of NA indicated some advantage in milk production. It can be assumed that with age the type of NA of cows changes from active (reactive) to calmer (inert). The proposed method of estimation of cows behavior in the milking parlour allows to group cows by type of NA, can improve cows welfare in the herd and optimize milk production. [ABSTRACT FROM AUTHOR]

The use of natural compounds such as herbs and herbal preparations because of their effects on animal health and product quality, is becoming a new goal in livestock production. Therefore, an experiment was carried to evaluate the effects of sweet marjoram on growth performance, rumen fermentation, meat quality and humoral immune response in Kermani lambs. A total of 24 Kermani lambs (27.5±0.450 kg) were distributed randomly into 24 individual cages in 3 experimental groups. The experimental diets consisted of the control and two experimental diet contained 2 and 4 % Origanum majorana leaf (OML) powder. The lambs were weighed and slaughtered after a feeding period of 80 days and meat quality were determined. OML powder had no effects on dry matter intake, but the apparent protein digestibility was higher linearly (P<0.05) for the diets containing OML powder. Live weight gain, final and carcass weight increased (P<0.05) with adding of OML in diet linearly. NH3-N concentration and protozoa population were less (P<0.05) with 2 and 4% OML than control. Fat and total protein linear decreased and increased (P<0.05) respectively in meat by adding of OML powder in diet, and longissimus dorsi of lamb fed OML powder had lower (P<0.05) malonaldehyde and cooking loss than the control diet linearly. The results suggest that OML is useful for improvement ruminal fermentation and is a suitable natural antioxidant in the meat production industry. [ABSTRACT FROM AUTHOR]

Delta-like 1 homolog or pre-adipocyte factor 1 (Dlk1) is one of the most significant genes and widely expresses all over mammal's development. Some of the functions identified for Dlk1gene are development of muscle, healing of wound, adipocytes proliferation, liver, lung and pancreas development. It also prevents Notch gene conducting toward to govern several operations such like cellular proliferation and differentiation. The aim of this study was to assay the expression of Dlk1 gene in liver, humeral and femur muscles, brain, adipose, testis and rumen tissues of Kermani lambs. Tissue samples from thirty male lambs of Kermani sheep with approximately the similar weight and age from the Animal Science Research and Training Station of Shahid Bahonar University of Kerman were picked up. Total RNA was isolated, cDNA was synthesized and Real-Time PCR was performed. SAS and REST softwares were used for analyzing the results. The Dlk1 gene was expressed in all studied tissues of Kermani sheep. The highest expression of Dlk1 gene expression was observed in liver tissue. There was no statistically significant difference between rumen and femur (leg) muscle, between humeral muscle and liver and between adipose and brain tissue (P>0.05). The lowest expression was related to testicular tissue. Based on results of current study, it can be concluded that this gene has pleiotropic effects with different major and minor outcomes in different tissues. But, for reaching to more decisive conclusion for any tissue, it is necessary to carry out further research noticing various physiological, epigenetic and genetic conditions. [ABSTRACT FROM AUTHOR]

The aim of this research was to investigate the changes in milk yield and its composition, fatty acid profile and peroxisome proliferator-activated receptors gamma (PPARG) gene expression in adipose tissue of Iranian Holstein cattle in response to feeding isonitrogenous and isocaloric diets but formulated based on different oilseeds (soybean or canola seeds). Twenty cows were tested randomly with experimental diets. Sampling from subcutaneous adipose tissue was performed. Moreover, fatty acid composition was analyzed, total RNA was isolated, cDNA synthesized and samples were amplified. SPSS 16.0, LinRegPCR and REST software were used to analyze real-time polymerase chain reaction results of gene expression. The amount of PPARG gene expression in the adipose tissue for canola seed treatment, in comparison with the soybean seed was higher. The milk production, 4% fat corrected milk, fat percentage, milk urea nitrogen and body condition score between two treatments was significant (P<0.05). The results showed that the amount of some fatty acids extracted from adipose tissue was changed by altering the diet. As, for C16:1, C18:0 and C18:3t fatty acids, there was a significant effect between the two treatments (P<0.05). In general, the PPARG gene expression was not significant in canola that can be due to the similarity of most of the fatty acids between canola and soybean, and the similarity and nutrient balance of the diet. Therefore, canola seed can be a good option for dairy cattle diet due to high levels of fat and protein and lower prices than soybean seed. It can also be used to improve milk, with the effect of feeding on the fatty acid composition of the milk. [ABSTRACT FROM AUTHOR]

The artificial neural networks (ANN) are the learning algorithms and mathematical models, which mimic the information processing ability of human brain and can be used to non linear and complex data. The aim of this study was to compare artificial neural network and regression models for prediction of body weight in Raini Cashmere goat. The data of 1389 goats for body weight, height at withers (HAW), body length (BL) and chest girth (CG) were used. Different regression models with all fixed factors were calculated for the most possible states and with different degrees and two artificial neural networks with different hidden layers, learning functions and transform functions were used. Finally, Multilayer perceptron model with one hidden layer along with neurons was selected and used. Correlation between body weight and its measurements showed that it is possible to use body measurements for prediction of body weight though prediction of body weight can be improved when more measurements are used. Based on R2 and mean square error (MSE) parameters, the best fitted regression equation for prediction of body weight using body measurements was selected. While all three measurements had a significant effect in the model (P<0.0001), height at wither had the highest correlation coefficient (0.65), hence may have the greatest effect on prediction. Comparing two models indicated that both models can predict body weight well and near to actual body weight, but the capability of artificial neural network model is higher (R2=0.86 for ANN and 0.76 for multiple regression analysis (MRA)) and closer to actual body weight. However, if more related measurements are recorded, ANN can give the desirable results. Therefore, it is possible to apply artificial neural networks, instead of customary procedures for prediction of actual body weight using body measurements. [ABSTRACT FROM AUTHOR]

Growth hormone (GH) has an effect on a broad variety of physiological parameters such as lactation, reproduction, growth and metabolism. Thus, the aim of this study was to detect GH gene polymorphism and its association with breeding values of production and reproduction traits in Raini Cashmere goat. Breeding values were estimated using records on 26731 Raini Cashmere goats. To study GH gene polymorphism, 300 animals were selected based on their estimated breeding values (EBVs) for these traits. Then the animal's genotype was determined using PCR-RFLP. The genotype frequencies for AA, AB and BB were 0.15, 0.85 and 0, respectively. The number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected homozygosity, observed homozygosity, Nei's index, Shanon's index and Fixation index (Fis) were 2, 1.96, 0.49, 0.85, 0.49, 0.51, 0.15, 0.49, 0.69 and -0.74, respectively. Results showed that mean estimated breeding values for birth type, fleece weight and birth weight traits in different genotypes varies, of course these differences were not statistically significant (P>0.05). However, for fleece weight and birth type traits AB genotype had higher EBV. Due to the relatively high diversity of growth hormone gene in Raini Cashmere goat and its association with important economic traits, using growth hormone gene in breeding programs of this breed can lead to acceptable genetic progress and applying AA genotype for birth weight trait and AB genotype for fleece weight and birth type traits can be used as an indirect marker for selection of superior animals. [ABSTRACT FROM AUTHOR]

The avian uncoupling protein (avUCP) is a member of the mitochondrial transporter superfamily that uncouples proton entry in the mitochondrial matrix from ATP synthesis. The polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method was used to estimate the allele and genotype frequencies of the UCP/HhaI polymorphisms and to determine associations between these polymorphisms and the growth traits, breeding value of growth and reproductive traits in the Fars indigenous chicken. For this purpose phenotype information of 18 successive generations from 200 birds were analyzed using a univariate animal model in ASREML procedure. The evaluation of the association between this single nucleotide polymorphisms (SNP) with reproductive traits suggests a positive effect of TC genotype with age at first egg (ASM) compared with CC genotype. In addition, TC genotype was significantly associated with the breeding value of age at first egg compared with the CC genotype (P<0.05). In conclusion, our results suggest that the TC genotype of the UCP gene is associated with age at sexual maturity (ASM) and breeding value of age at sexual maturity and UCP polymorphisms may be used as DNA markers for selection in the breeding process of the Fars indigenous chicken. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine characteristics of Rheb gene and protein in Raini Cashmere goat. Comparative analyses of the nucleotide sequences were performed. Open reading frames (ORFs), theoretical molecular weights of deduced polypeptides, the protein isoelectric point, protein characteristics and three-dimensional structures was predicted using online standard softwares. The full cDNA nucleotide sequence shares 99%, 99%, 99% and 94% identity with Inner Mongolia Cashmere goat, cattle, horse and human, respectively. The deduced Rheb protein of Raini Cashmere goat consist of 184 amino acid residues and its predicted molecular weight was 20478 g/mol for the unmodified protein and the estimated isoelectric point (pI) was 5.59. Results showed that Rheb has a RAS domain starting at the amino acid 4 and ending at the amino acid 170. In conclusion, our data shows the Rheb cDNA is 555 bp in length, including a complete ORF corresponding to a polypeptide of 184 amino acids. Our results in Raini Cashmere goat showed that there are 1 N-glycosylation sites, 3 protein kinase C phosphorylation sites, 2 casein kinase II phosphorylation sites, 4 microbodies C-terminal targeting signals, 2 ATP/GTP binding sites motif A (Ploop) and a prenyl group binding site for predicted Psites of Rheb. Raini Cashmere goat Rheb protein also had an interaction with other predicted proteins. Hence, can suggest that Rheb has probably role in goat cells and must detect in future investigations. [ABSTRACT FROM AUTHOR]

Cattle supply an important source of nutrition for humans in the world. CpG islands (CGIs) are very important and useful, as they carry functionally relevant epigenetic loci for whole genome studies. As a matter of fact, there have been no formal analyses of CGIs at the DNA sequence level in cattle genomes and therefore this study was carried out to fill the gap. We used hidden markov model algorithm to detect CGIs. The total number of predicted CGIs for cattle was 90668. The number of detected CGIs and CGI densities downwardly varied across chromosomes. Chromosome 25 had the largest number of CGIs (4556) and the highest CGI density (106.20 CGIs/Mb). A significant positive correlation observed among CGI densities with guanine-cytosine (GC) content, ObsCpG/ExpCpG, recombination rate and gene density. When the size of chromosomes increased, the CGI densities decreased and a trend of higher CGI densities in the telomeric regions observed. This feature may be the reason of a positive correlation between CGI density and recombination rate. To detect information on CGI density differences between cattle and other vertebrate genomes, CGI density was also scanned in eleven vertebrate genomes. The CGI densities varied greatly among genomes. These discoveries may contribute to a better understanding of epigenomic role of CGIs and their molecular evolution in the cattle. [ABSTRACT FROM AUTHOR]

In this experiment six healthy adult dairy Jersey cattles and eight calves (aged 4-6 months) were selected to measure temperature of different body skin sites, rectal temperature, respiration and heart rates during summer and winter. Body sites maximum and minimum temperature in calves during summer belonged to the ear, forehead, right flank, abdomen (38.4-38.9 °C) and carpus (32 °C). This was also true for the foreleg, abdomen, tail (38-38.15 °C) and tarsus (33.9 °C) of cattle, respectively. The minimum body temperature of all these animals was detected in the carpus and tarsus. Correlation coefficient was significant between rectal and tail temperatures (r=0.61; P<0.01). Also, there was significant correlation of respiration rate with abdomen, dewlap, neck, tail and rump temperature, but maximum coefficients were related to respiration rate with ear, forehead and tail temperature (r=0.8-0.91; P<0.01). Heart rate had maximum correlation with ear and forehead as well. It is concluded that both abdomen and tail and also other body sites, such as ear and neck, had significant role in body heat loss. Cattle heat dissipation to the environment is through the skin of their tail and ear and these have a higher correlation with respiration, heart rate and rectal temperature. [ABSTRACT FROM AUTHOR]

The pituitary-specific transcription factor (PIT1) gene is responsible for pituitary development and hormone secreting gene expression in mammals. PIT-1 is studied as a candidate genetic marker for growth, carcass and also for milk yield traits. In dairy farm animals, the principal goal of the selection is the improvement of milk yield and composition. The genes of milk proteins and hormones are excellent candidate genes for linkage analysis with quantitative trait loci (QTL) because of their biological significance on the quantitative traits of interest. Thus, in this study association between polymorphism of the pituitary transcription factor 1 (PIT1) gene and milk fat percentage of Holstein cattle in Khorasan Razavi province of Iran were analyzed. A total of 100 dairy cows from a herd containing 1000 animals were included in the study. Genomic DNA was extracted from the whole blood. One pair primers were used for amplification of PIT1 gene and PCR products were electrophoresed on 1% agarose gel. Then, PCR products were digested with HinfI restriction enzyme. Results were analyzed using PopGene software and allele frequencies A and B were 0.25 and 0.75, respectively. Frequencies of AA, AB and BB genotypes, number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected hemozygosity, observed hemozygosity, Nei's index and Shanon's index were 6, 40 and 54%, 2, 1.6, 0.37, 0.40, 0.37, 0.62, 0.59, 0.37 and 0.56, respectively. Results of k-square shown that population is in Hardy-Weinberg equilibrium. SAS software with GLM procedure was used for calculation of association between milk fat percentage and observed genotypes and results indicated that the effect of genotype on fat percentage was significant (P<0.01) and AB genotype had the highest effect on milk fat percentage. These results imply that the PIT1 genotypes affected milk fat percentage, suggesting that this polymorphism can be used as a molecular marker for this trait. [ABSTRACT FROM AUTHOR]

Clostridium perfringens is an important pathogen that provokes numerous different diseases. This bacterium is classified into five various types, each of which capable of causing a distinct disease. There are various methods for the bacterial identification, many are labor-intensive, time-consuming, expensive and also show low sensitivity and specificity. The aim of this research was to identify the unlike types of Clostridium perfringens using PCR method. In this study, 120 ostrich-dung samples were randomly collected from areas around the city of Kerman, southeastern Iran. After processing and culturing of samples, the produced colonies were morphologically studied, gram stain test was also carried out and the genera of these bacteria were identified through biochemical tests. DNA extracted from isolated bacteria for genotyping was tested by multiplex PCR with specific primers. Based on length of synthesized fragments by PCR, toxin types and bacterial strains were detected. Clostridium perfringens isolated types were divided as follows: 100% type A, 0% type B, 0% type C and 0% type D. It should be emphasized that, up to now, Clostridium perfringens type A has not been reported in Iran. [ABSTRACT FROM AUTHOR]

A three-generation resource population was developed using two distinct Japanese quail strains, wild and white, to map quantitative trait loci underlying hatching weight and growth traits. Eight pairs of white and wild birds were crossed reciprocally and 34 F1 birds were produced. The F1 birds were intercrossed to generate 422 F2 offspring. All of the animals from three generations (472 birds) were genotyped for eight microsatellite markers on chromosome 1. Liveweight data from hatch to 5 weeks of age were collected on the F2 birds. Quantitative trait loci (QTL) analysis was conducted applying the line-cross model and the least-squares interval mapping approach. The results indicated QTL affecting hatching weight and several growth related traits on chromosome 1. The F2 phenotypic variance explained by the detected additive QTL effects ranged from 1.0 to 3.7 for different traits. Modelling both additive and dominance QTL effects revealed additional QTL with significant dominance mode of action affecting pre-slaughter weight. However, there was no evidence for imprinting (parent-of-origin) effects. The variance due to the reciprocal cross effect ranged between 3.0 and 19.1% for weight at 1 week of age and hatching weight, respectively. Genetic mapping of loci underlying economic traits in Japanese quail is of great interest both for biologists and animal breeders. The results of this study indicated significant regions on chromosome 1 affecting hatching weight and growth-related traits. These results pave the way for future gene discovery in Japanese quail as an animal model species. [ABSTRACT FROM AUTHOR]

Synthetic gene transfer vectors based on zwitterionic nanoliposome-DNA assemblies (nanolipoplexes), formed by the mediation of magnesium ions, were prepared by a scalable method without employing volatile solvents, high-shear force treatments or extrusion. The zwitterionic nanolipoplexes (NLP) were formulated with PC (phosphatidylcholine) and DPPC (a natural lung surfactant) incorporating different amounts of cholesterol (CHOL). The resulting structures were characterised in terms of their morphology, size and DNA content. In addition, the toxicity and transfection efficiency of the nanolipoplexes were evaluated in cultured Chinese hamster ovary-K1 (CHO-K1) cells. The effects of the multivalent cation Mg2+ on nanoliposome-DNA transfection potency were evaluated. Formulations containing 10% CHOL showed maximum transfection efficiency and the optimum amount of Mg2+ ions for transfection with minimum cytotoxicity was ca. 20 mM. The zwitterionic formulations showed significantly less cytotoxicity compared to a commercially available cationic liposome reagent or polyethylenimine (PEI) while they were superior in terms of gene transfer potency. The zwitterionic vectors formulated in this study avoid the use of toxic cationic lipids as well as toxic solvents and may have potential application in gene therapy. The new method will enable scale-up and manufacture of safe and efficacious transfection vehicles required for preclinical and clinical studies. Based on the advantages and superiority of the formulated nanolipoplexes, this method allows for the acceleration of nanolipoplex formulation, enabling the rapid development and evaluation of novel carrier systems for genes and other drugs. [ABSTRACT FROM AUTHOR]

The prolactin gene (PRL) is a potential candidate gene for the goat cashmere traits in marker-assisted selection. Thus, the aim of this study was to detect PRL gene polymorphism and its association with fiber traits in 200 Raini cashmere goats native to the south-east of Iran. A 196-bp fragment encoding exon 5 within the goat PRL gene was amplified using PCR specific primers. The amplification products were subjected to the single stranded conformation polymorphism (SSCP) analysis. Three different SSCP banding patterns (CC, AC and AA) were observed in exon 5 of the caprine PRL gene. The pattern frequencies for CC, AC and AA were 0.39, 0.38 and 0.23 and frequencies of the A and C alleles were 0.42 and 0.58, respectively. The genotypic distributions did not deviate from the Hardy-Weinberg equilibrium (P> 0.05). The number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected homozygosity, observed homozygosity, Nei's index and Shanon's index were 2.0, 1.9, 0.48, 0.38, 0.48, 0.51, 0.61, 0.48 and 0.68, respectively. Results of association between genotypes and fiber traits indicated that the CC genotype had the highest fiber length compared with the AA and AC genotypes (P < 0.05) while there was no significant association between the PRL gene genotypes and fiber diameter. These results imply that the PRL gene polymorphism can be used as a molecular marker to improve fiber production without a negative effect on fiber diameter.

Bovine leukemia virus (BLV), the causative agent of enzootic bovine leukosis, is an exogenous, B lymphotropic retrovirus belonging to the Retroviridae family that induces persistent lymphocytosis in cattle and sheep. PCR has proven to be particularly suitable for investigating herds of cattle with a very low incidence of BLV infection and for clarifying doubtful serological results obtained by immunodiffusion or ELISA. The native Iranian and Russian cattle have a series of valuable traits that discriminate them as unique breeds that are well able to compete with western analogues. However, their gene pools have not been analyzed with molecular markers, including detection of BLV by PCR. Two pairs of primers were used: gag1 and gag2, and pol1 and pol2, which encompass 347- and 599-bp fragments of the BLV gene, respectively. Sixty-five Iranian Sistani, 120 Yaroslavl, 50 Mongolian, and 35 Black Pied cows were investigated. Among these 270 animals, we obtained 42 positive and 15 doubtful results in the first PCR. The second PCR was very effective in increasing BLV test reliability data to support detection of BLV.

The oral route is considered the most patient-convenient means of drug administration. In recent years there has been a tendency to employ smart carrier systems that enable controlled or timed release of a bioactive material, thereby providing a better dosing pattern and minimizing side effects. Nano-encapsulation systems (nanocarriers) offer important advantages over conventional drug delivery techniques. Nanocarriers can protect the drug from chemical/enzymatic degradation and enhance bioavailability. Prebiotics are ideal ingredients for the nano-encapsulation and oral drug delivery due to their natural ability to protect the encapsulated compound in the upper gasterointestinal (GI) tract. Here the potential of prebiotics for oral delivery of drugs and other bioactives is reviewed.

Polymorphism of the BoLA-DRB3 gene was studied with the use of the PCR-RFLP technique in three cattle breeds (Mongolian, Kalmyk, and Yakut) representing the Bos taurus turano-mongolicus group. 35 BoLA-DRB3.2 alleles were detected in the Mongolian breed and 34 alleles in the Kalmyk breed. The frequencies of alleles in both populations are distributed rather evenly: the frequencies of the most widely represented alleles (*18, *20, and *28) in the Mongolian cattle varied from 7.75 to 8.45%. The most frequent alleles in the Kalmyk cattle were *28(14.52%), *24(7.26%), and *12(6.45%). Only five alleles were identified in the Yakut cattle breed. The prevailing allele was *29 (77.3%); a relatively frequent allele was *1(13.1%), and the remaining three alleles constituted only 9.6%. Such a low level of diversity of BoLA-DRB3 gene alleles was not observed earlier in any other cattle breed. The Mongolian and Kalmyk breeds showed a wide diversity of BoLA-DRB3 genotypes (56 and 51 genotypes, respectively) and a high level of expected heterozygosity (He = 0.953 and 0.946, respectively). Both breeds had a deficiency of heterozygotes (Mongolian cattle: Ho = 0.775, D = -0.187; Kalmyk cattle: Ho = 0.708, D= -0.252). A low level ofgenotypic diversity for the BoLA-DRB3 locus (only seven genotypes; the frequency for the genotype *29/*29 is 71.4%) and a very low level of observed heterozygosity (Ho = 0.12) were revealed in the Yakut breed. BoLA-DRB3.2 alleles associated with resistance to persistent lymphocytosis caused by the bovine leukemia virus (total frequencies 15.49 and 24.19%) and to various forms of mastitis (total frequencies 12.68 and 20.96%, respectively) were identified in the Mongolian and Kalmyk animals. In the Yakut breed, alleles associated with resistance to diseases are represented only by the BoLA-DRB3.2 allele *7 (1.2%). Thus, the Mongolian and Kalmyk cattle breeds are characterized by a wide diversity of alleles and genotypes for the BoLA-DRB3 gene. In contrast, the population of Yakut cattle from the Verkhoyanskii raion of the Republic of Sakha has a poor diversity of alleles and genotypes for the BoLA-DRB3 gene and a very low level of heterozygosity, suggesting an unfavorable state of the population that is probably caused by inbreeding depression due to a long-term isolation and a small number of animals.

The distribution of the frequencies of BoLA-DRB3 gene alleles in the Iranian cattle breed Sistani was studied by the PCR-RFLP ("hemi-nested") assay using restriction endonucleases RsaI, HaeIII and BstYI. In the examined cattle breed (65 animals) 32 alleles have been identified one of which being described for the first time (6.15% frequency). The nucleotide sequence of the polymorphic region of exon 2 of this allele has been determined and submitted in the GeneBank database under accession number DQ486519. The submitted sequence has maximum homology (92%) with the previously described sequence DRB3-mRNA from Bos indicus (AccN X79346) and differs from it by 24 nucleotide substitutions which result in 16 amino acid substitutions. The peptide (on the basis of the reconstructed amino acid sequence) has 89% identity to the sequence encoded by the BIDRBF 188 locus (Bos indicus). The results obtained permit the sequence described by us to be considered as a new allele of the BoLA-DRB3 gene (DRB3.2**X). The total frequency of the main six alleles (DRB3.2*X, *10, *11, *20, *34 and *X) occurring with a frequency of over 5% is about 60% in Iranian Sistani cattle. Fifteen alleles have <1% frequency. The highest frequency was observed for DRB3.2*8 allele (21.54%) like in other previously described breeds of Bos indicus (up to 23.07%). The Iranian breed Sistani has a high level of similarity by the spectrum of BoLA-DRB3 alleles and their frequencies to other Bos indicus breeds and significantly differs by these criteria from the Bos taurus breeds. The Iranian Sistani herd under study includes alleles associated with to resistance to leukemia (DRB3.2*ll and *23) and to different forms of mastitis (DRB3.2*2, *7, *11, *23 and *24) although their frequencies are low (from 0.77 to 5.37%). On the whole, a high level of diversity of BoLA-DRB3 gene alleles and the availability of alleles associated with resistance to different diseases makes this breed of interest for breeding practice.

The main goal of breeders is breeding superior animals. Most traits of the economic importance in farm animals are determined by polygenic loci with environmental factors. Progress in animal breeding may be improved by combining traditional performance data with molecular genetic information on quantitative loci in selection index. Candidate genes are chosen for study on the basis of known relationships between biochemical and physiological processes. Leptin is 16 KD protein that is synthesized by adipose tissue and it is involved in the regulation of feed intake, energy balance, fertility and immune functions. In cattle, the leptin gene is located on chromosome 4. It consists of 3 exons and 2 introns of which only two exons are translated into protein. Sixty six animals were genotyped for this project. A PCR was carried out between 2 exon (intron 2). A strategy employing polymerase chain reaction was used to amplify a 422 bp from blood, semen, hair root and milk DNA. Digestion of polymerase chain reaction products with Sau3AI revealed two alleles: Allele A was 390, 32 fragments and allele B was 303, 88, 32 (only 303 fragment visible on the gel). Three patterns were observed and frequencies were 0.31, 0.43, and 0.14 for AA, AB and BB respectively. This polymorphism could be further evaluated for marker assisted selection and developed PCR methodology would expedite screening for large numbers of animals required for such studies.