Background and Objective: Gastric cancer is the second cause of cancer mortality after lung cancer. Approximately 12% of all cancer death are due to gastric cancer. Tumorgenesis is thought to be a multi step process involving a series of genetic changes in oncogenes and suppressor genes. The most common cancer-~elated genetic change known in human tumors is p53 mutation, particularly in gastric cancer. This sutdy was done to determine p53 gene Mutations in gastric cancer. Materials and methods: This study was perfomed on 44 biopsy from patients with gastric cancer during 2002 in three hospitals in Tehran. For determination ofp53 gene Mutations was performed PCR-SSCP methods Results: The patients group comprised 31 males and 13 females (average age, 60.8 years; ranging from 34 to 84 years). 36 cases (81.8 %) intestinal type, 5 cases (11.4 %) were diffuse type and 3 cases no defined. Forty-four gastric cancers of gastric tissues were screened for the mutations of p53 gene mutations in Exons 5-8 using the PCR-SSCP analysis. After polyacrylamide gel electrophoresis, nine patients (20.5%) showed an apparent electrophoretic mobility shift between the cancer and other normal samples. One mutation in Exon 5 (11.1 %), two were detected in Exon 6 (22.2 %), three were found in Exon 7 (33.3 %), and three were detected in Exon 8 (33.3%). The mutation rate was seven of36 (21.2%) in intestinal type and two of (40%) in diffuse type. No significant correlation between p53 gene mutations and age and genus was found. Conclusions: This Investigation showed the rate ofp53 gene mutation (20.5%) in gastric cancer in our socitey.

It has been shown that the occurrence of any changes in the function of DNMTs genes has a significant effect on both the embryo development and birth weight in mammals; therefore, the aim of the present study was to investigate the presence of DNA polymorphisms in the members of DNA methyl transferase superfamily and its relationship with birth weight in Sistani cattle’ s. Blood sampling was done randomly from 60 Sistani cows. DNA extraction was performed using phenol chloroform method. Candidate region for the presence of functional polymorphism within the DNMTs gene including the 114-bp fragment of the exon 33 of the DNMT1 gene, the 176-bp fragment of the intron 4 of the DNMT3a gene, and the 207-bp fragment in intron 3 of the DNMT3b gene were amplified by polymerase chain reaction. PCR-SSCP followed by polyacrylamide gels silver stain analysis was done to evaluate the presence of candidate mutations in target gens. The result analysis of all analyzed region did not show any mutations in the investigated DNMTs genes. Based on the results of this study, it seems that the lack of observation of genetic diversity in the studied regions could be related to the evolutionary selection against occurrence of specific mutations in the analyzed population. In general, based on the results of this study, analysis of genetic diversity in the studied genomic region may not be effective in identifying effective markers for breeding programs in Sistani cows.

Identification of associated genes with energy balance, yield and feed intake are recent interests of the animal breeding researchers. With consider to rich resources of animals, in our country-Iran, accomplish a little assay for identification of genes that controlling its traits with molecular techniques. Identify the candidate genes in sheep breeds using DNA test can have a great help for their breeding progress. In this research, for analysis of leptin gene polymorphism in Kermani sheep, we collected blood samples of one hundred and twenty male and female Kermani sheeps which were rearing in breeding center of Shahre Babak, Kerman. Genomic DNA was extracted using commercial DNA extraction Kit. The exon 3 (275 bp segment of exon 3) of leptin gene was amplified with specific primers. The single stranded conformation polymorphism (SSCP) patterns of PCR product were studied using Acrilamid gel and silver staining method. We obtained 10 band patterns for leptin gene: A/A, C/C, A/B, A/C, A/B/C, A/B/E, A/B/F, A/C/F, A/B/D/E and A/B/C/F. The results showed that leptin gene is so polymorphic in studied population.

Background and Aim: b-thalassemia (b-thal) is one of the most prevalent hereditary diseases in Iran. There are more than two million carriers of b-thal in Iran. Detection of the beta globin gene mutations is necessary for a definitive diagnostic and management plan such as prenatal diagnosis of b-thalassemia. In our country, the PCR-Amplification Refractory Mutation System (PCR-ARMS) has been frequently used for detection of beta globin gene mutations.Material and Methods: Here, we used the PCR-single strand conformation polymorphism (PCR-SSCP) assay for detection of mutations of beta globin gene. In the patients with confirmed mutations, we amplified 281base pairs containing exon of one of a beta globin gene by PCR. Based on SSCP technique 2.5 ml of the reaction products appeared in polyacryamide gel electrophoresis and the bands were visualized by silver staining. Seven mutations and one polymorphism were evaluated by PCR-SSCP assay.Results: The results of this study demonstrated that the patterns of mobility of single strands were different from each other and those of control sample.Conclusion: Our study showed the PCR-SSCP technique can meet the need for direct genomic sequencing of DNA and could be applied in the developing countries where financial resources are limited but genetic hemoglobin disorders are highly prevalent. Key words: Thalassemia, SSCP, b-globin gene.

Due to their roles in regulating embryonic growth and development members of DNA Methyltransferases (DNMTs) family have been shown to play fundamental parts in embryonic fertilization to postnatal life; through regulating the establishment and/or maintenance of specific epigenetic marks. The present study was conducted to identify potential reported mutations within the exon 33 of DNMT-1, introns 4 of DNMT-3a and introns 3 DNMT-3a genes and their relationship with birth weight in Iranian Holstein cows. A total of 60 blood samples from Holstein dairy cattle with records of weight from birth to adult age were randomly collected from industrial dairy cattle farm located in Kerman province. Genomic DNA samples was extracted using Phenol-Chloroform method and target sequence was amplified with PCR using specific primers. Polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) and silver nitrate staining methods was used for screening potential mutation in target sequences. According to results of this study, in all cases, no mutation in target sequence were identified as all samples had the same specific SSCP pattern with respect to their size. The lack of polymorphism may imply that these region may be attributable to a relative inefficiency of PCR-SSCP for mutation detection, small sample size, stochastic effects of genetic drift and/or conserved nature of these genes due to either natural or artificial selection. According to the results of this study, analyzed sequence may not be informative as molecular marker for birth weight in Holstein cattle.

Hemophilia B is an X-linked recessive bleeding disorder caused by heterogeneous mutations in factor IX gene. In about one-third of cases it arises by a new mutation in germ-line cells. In this study carrier testing was performed for females of a family with only one affected individual by single strand conformation polymorphism (SSCP). Results indicated that the SSCP band shift in the propositus was de novo and his mother and also sisters were not carrier. This finding was also confirmed by sequencing.