MODERN GENETICS JOURNAL (MGJ)
Year:2012 | Volume:6 | Issue:4 (27)|Papers Count:14

with the completion of the Human Genome Project, the list of the genes needed to produce a perfect human was completed. Of equal importance is a second system that cells use to determine when and where a particular gene will be expressed during development.However, the situation is far more complex than a simple catalogue of genes. Classical genetics alone cannot explain the existing diversity of phenotype. The concept of epigenetic offers an explanation and description of these phenomena. The best-known epigenetic marker is DNA methylation. In human, DNA methylation occurs at the C-5' position of cytosine within the CpG (5' -CG-3') dinucleotide. Methylation of DNA plays a pivotal role in the control of gene activity and nuclear architecture. Aberrant DNA methylation (Genomic global hypomethylation and region-specific hypermethylation) is frequently observed in aging and especially in the tumorgenesis. Today, epigenetic researches are focused on studying and increasing understanding of the mysteries and ambiguities in the complex biological processes like cancer and aging. Recent studies have shown that dietary factors can modulate DNA methylation and thereby contribute to aging and tumorgenesis. Thus, DNA methylation provides an important common link between aging, cancer and nutrition.

recent studies have indicated that genetic polymorphisms of the specific genes is one of the causes of miscarriage. In the other hand it is observed that nitric oxide (NO), as a signaling molecule, is participated in primary events of pregnancy such as implantation of blastocyte, differentiation of trophoblast, trophoblast invasion, and it enhances blood supply through the maternal arteries to the placenta thus it has a role in implantation and maintenance of pregnancy. NO is produced by endothelial nitric oxide synthase that is expressed in placenta, whereas this enzyme and its production play a key role in early stages of gestation, we investigated relationship between polymorphism of this gene and complication of pregnancy. In this study we used 100 women who had three or more constitutive miscarriage with unknown reason in first trimester of their pregnancy in case group. Control group is included 100 women with normal pregnancy. Both group were analysed for VNTR polymorphism in intron4 of endothelial nitric oxide synthase gene by PCR and also were analysed for Glu298Asp polymorphism in exon 7 of this gene by PCR-RFLP and sequencing. Genotype frequency of VNTR polymorphism in case group is 63% (bb), 33% (ab), 4% (aa) and in control group is 79% (bb), 18% (ab), 3% (aa). The genotype frequency of Glu298Asp polymorphism in exon7 is as follow: 71% (GG), 25% (GT), 4% (TT) in case group and 68% (GG), 29% (GT), 3% (TT) in control group. Our data indicate that the “a” allele frequency is significantly different between case and control group but other data do not show difference. Therefore a allele of VNTR polymorphism of endothelial nitric oxide synthase gene is a risk factor for RSA but T allele don’t have any role.

Litter size is one of the most important economical traits in sheep breeding and recent discoveries have shown that it is influenced by a number of major genes. The high prolificacy in Inverdal and Hanna sheep is the result of a mutation in the BMP15 oocyte-derived growth factor gene.This study was carried out for detection of possible polymorphisms in FecXI and FecXH genes. PCR-RFLP method was used to develop FecXI and FecXH mutant allel. This study was performed using blood samples, collected from 239 ewes of Shall sheep. Genomic DNA was extracted using modified salting-out method. The polymerase chain reaction (PCR) was carried out for amplification of a fragment with 204 and 235 bp at the mentioned loci respectively. For genotyping the individuals at Inverdal and Hanna loci, the resulted amplified fragments were digested using XbaI and SpeI restriction enzymes respectively. XbaI and SpeI restriction enzymes were used to detect possible mutation through which Shall breed sheep was tested for the presence of the FecXI and FecXH mutation of BMP15. There were no evidence of FecXI and FecXH in shall breed sheep samples all individuals in the sample showed wild genotype (++). Considering the phonotypic records, the obtained result indicates that in this breed, the relationship of genetic factor responsible for twining or multiple lambing rates with reported mutated alleles at Inverdal and Hanna major gene is very unlikely.

although molecular markers have been successfully used to analyze genetic variability within and among perennial forage grasses, examples of applications to benefit their breeding programs are rare. Additionally, molecular information about effect of genetic diversity on performance of synthetic cultivars and their application toward parental selection are limited. In this study, 25 tall fescue genotypes were selected from a base population and the genetic diversity among them was assessed using morphological (12 Agro-morphological traits) and molecular (using 50 EST-SSR primers) characteristics. For each morphological and EST-SSR evaluation, two polycross of six parental plants with contrasting levels of genetic diversity (narrow and wide) were composed and the corresponding synthetic varieties were morphologically evaluated. Average genetic diversity among parents selected for narrow polycrosses in molecular and morphological analysis was 55% and 14% lower than among parents selected for wide polycrosses, respectively. Results showed that progenies from molecularly wide polycross had significantly higher hay yield (25%), stem number (12%) and crown diameter (10%) when compare to progenies from molecularly narrow polycross. Morphological diversity did not affect these traits. On the other hand, higher morphological diversity increased days to pollination and plant height by 4.5 and 7% respectively. Results indicated that progeny performance in tall fescue can be estimated by molecular information of their parents. The results provide evidence for an efficient application of molecular markers to select genetically diverse parents especially for quantitative traits.

introduction: Colorectal cancer is one of the most common forms of cancer in the world. Among several genetic events which have been documented in colorectal tumour progression, K-ras has high diagnostic value. Studies have shown that K-ras mutations are found in 20-50% of all colon cancers mostly in codons 12 and 13, and less frequently in codon 61.The aim of the present study is to identify K-ras gene mutations in codon 13 in CRC patients among the East-North of IRAN, and to assess whether they are linked to the clinicopathological parameters. Materials and Methods: Tumor samples were collected from a consecutive series of 54 patients undergone respective surgery for CRC.DNA was extracted from tumour and RFLP-PCR was applied for codon 13 mutation detection. Results: The results reveal that 18.51% of the patients (10/54) have the mutation in the K-ras gene-codon 13. In the present study, K-ras mutations were significantly associated with CRC stage (P<0.05). No significant correlations were found between the mutations and sex, grade and tumor location.Conclution: The research shows that mutations in K-ras gene-codon 13 have a significant role in tumor type cell progression in CRC patients; therefore, screening for K-ras mutations appears to have a high prognostic value for evaluating of the risk of the tumor progression.

in this research genetic diversity of 33 M7 soybean mutant lines with high N2 fixation characteristic which evolved from L17 cultivar irradiated by γ ray (co-60) doses 150, 200 and 250 Gray (absorbed dose), L17 cultivar and two commercial cultivar; Clark (CL) and Williams (WI) were studied using random amplified polymorphic DNA (RAPD) markers. RAPDs established 104 major amplified products using 10 polymorphic primers. Out of 104 markers, 34 were monomorph and the remaining (70) were polymorph. To estimate the similarities amongst mutant lines, parent cultivar and commercial cultivars, the Jacard coefficient provided similarity values ranging from 0.17 to 0.79. Clustering of studied genotypes with cluster analysis method and by CL (completely linkage) algorithm resulted in 7 major groups. Regarding to the similarity matrix, the mutant lines number 32 (M32) and number 9 (M9) were closer and entirely different from parent cultivar respectively. According to the high genetic variability of these mutant lines, they can use in future plant breeding programs to create desirable cultivars.

hybridization is one of the traditional methods of breeding in agriculture and aquaculture as well. Hybrid nature detection has a key role in this valuable breeding plan. For this purpose, we can use different methods; molecular method is one of the most important and pioneering methods for hybrid detection. In this research the possibility of RAPD marker to evaluate hybridization between female rainbow trout Oncorhynchus mykiss and male Caspian trout Salmo trutta caspius was analyzed. For this purpose 30 RAPD primers were randomly selected and parents’ genotypes were analyzed through PCR. Only 2 out of 30 primers including H-09 5’TGT AGC TGG G3’ and P-12 5’AAG GGC GAG T 3’ showed remarkable polymorphism and clear specific bands between at least one pair of broodfish. All (except one) F1 larvae inherited total specific bands of two parents which completely confirmed the accuracy of hybridization between two species. In this research the efficiency of RAPD marker to evaluate hybridization between two commercial salmonid species in Iran was documented.

the use of genetic resources in crop improvement requires accurate study of genetic diversity in plant populations. Therefore, genetic structure and diversity of 80 alfalfa (Medicago sativa L.) genotypes belong to 8 population were assessed using ISSR markers. Sixteen ISSR primers amplified a total of 117 loci, out of them 91 were shown to be polymorphic among and within populations.PIC (Polymorphic information content) values for primers ranged from 0.65 (Primer UBC849) to 0.93 (primer 443), averaging 0.77. Populations were grouped in three main clusters using UPGMA algorithm based on Nei genetic distance coefficient. The maximum and minimum amount of genetic distances between populations were 0.128 (Gharayonjeh-malekkandi and Hamedani) and 0.054 (Turkey-sakuel and Baghdadi), respectively. Mean of heterozygocity varied from 0.267 (Baghdadi) to 0.309 (Turkey-sakuel and Mahalie-esfahani) with an average of 0.285. Analysis of molecular variance (AMOVA) showed that 91% of the total genetic variation was attributed to intra-population variance. Cluster analysis based on complete linkage algorithm using Dice similarity coefficient identified 6 heterotic groups among studied genotypes. Populations with enough genetic distance or genotypes belong to different heterotic groups could potentially introduced as crossing parents in alfalfa breeding programs.

in this study, the induced responses of Jam chickpea in cold acclimation and cold stress temperatures have been assayed by detecting electrolyte leakage index (ELI), malondialdehyde peroxidation of membrane lipids (MDA) and the activity of catalase (CAT) enzyme. After exposing plants into cold acclimation situation, they showed more readiness in facing up zero temperature and more clearly in facing below zero cold stress. The results have shown a potent variety in the level and speed of cell responses in this genotype and the extent of CAT activity, as cell defense system, is matched with ELI and MDA result, as damage indexes. Detecting plants in recovery phase have shown that the increased tolerance in cold acclimation is a temporary situation and after passing cold stress, not only CAT activity will decrease but also the amount of damage in cell membrane will decline. So, inducing cold acclimation treatment increase plant tolerance in cold stress and enhance plant survive and inducing this treatment can cause plant recovery even after sever cold stress.

nearly completed sequenced genome of maize has changed it to an appropriate crop for genetic studies. In the current study variation of recombination frequencies along the chromosomes and segregation distortion regions were investigated using 71 maize recombinant inbred lines. A linkage map including 686 SNPs was used to evaluate the variation in recombination frequencies in maize genome. A total of 151 SNPs from 714 polymorphic SNPs were deviated from expected Mendelian segregation (1: 1) at 5% probability. In ten linkage maps, a total of 8 SDRs was detected. One of detected SDR was co-segragated with gametophyte factor 2 (ga2). The range of recombination frequencies variation was between 0.06 and 8.47. Also a long condense heterochromatin region (knob) was detected at long arm of chromosome 4. Approximate location of centromeres also was determined. Information about relationship between physical and genetic distances along chromosomes and location of SDRs could be used by breeders and genetic researchers in different ways.

translocation incidence of chromosomal balanced chromosomal abnormalities in couples with repeated abortions is from 0-31% different studies indicate that recurrent spontaneous abortions to prove Translocation balanced are helpful. In this study, 75 couples had 3 abortions and 65 couples had two abortions. These patients were referred by specialist of women investigated cytogenetically to the lab Beheshti Hospital of Hamadan. and the karyotype 40 healthy individuals without history of abortion Embryos investigated as control group and study made. this study is prospective.in this study used GTG bonding technique (stained with gymsa and trypsin). Frequency of chromosomal abnormalities and Hetromorphism between couples with three or more abortions were reported, respectively 5.3% and 9.3%. as the frequency of chromosomal abnormalities among couples with two abortions were determined for chromosomal abnormalety 3.07% and 6.15% Hetromorphism Chromosomal. Controls the frequency of chromosomal Hetromorphism of 7.5% was driven and no chromosomal abnormalities were observed in control subjects. This results show that chromosomal abnormality is one of the reasons is recurrent spontaneous abortions that more abortion increases the probability of this anomaly.also chromosomal Hetromorphism of the general population of individuals without history abortion embryos indicate that Hetromorphism Chromosomal can not be the reason of these spontaneous abortions.