GENETICS IN THE 3RD MILLENNIUM
Year:2011 | Volume:8 | Issue:4|Papers Count:10

This study was conducted on Iranian children with oligoarthritis subtype of juvenile rheumatoid arthritis to determine the association of HLA-DRB1 alleles in Iran. HLA-DRB1 alleles were investigated in 33 Iranian children with oligoarthritis juvenile rheumatoid arthritis and compared with 45 healthy controls. HLA typing was performed by PCR with sequence specific primers in either two groups and followed by direct detection of HLA polymorphism by sequence analysis in patients group. HLA-DRB1 11 was found to be the most frequent allele associated with negative rheumatoid factor oligoarthritis juvenile rheumatoid arthritis in Iran, followed by HLA-DRB1 08. The frequency of HLA-DRB1 04 and 13 were not significantly different between the two groups. It could be concluded that there was a significant difference in allele frequencies between patients and controls that might help with predicting the susceptibility to oligoarthritis juvenile rheumatoid arthritis.

Genomic DNA extraction with desirable quantity and quality is a basic requirement in molecular biology. Most commercial DNA extraction methods the time-consuming and based on use of enzymes (proteinase K) and toxic organic solvents (phenol-chloroform). Therefore, since these enzymes are expensive and materials are harmful, DNA extraction methods that are void of such disadvantages are required. In this study, buffer/detergent extraction method and salting-out method in different species including blood samples of cattle, sheep, goat and chicken and semen samples of bulls and rams were studied. For DNA extraction and comparison of two methods, 366 blood samples and 26 sperm samples were used. Quantity and quality parameters using Nanodrop and agarose gel (1%) and efficiency PCR (Polymerase Chain Reaction) were evaluated in both methods. Concentration and purity of the extracted DNA were 623.8± 198 mg/mL and 1.87 ± 0.05 respectively in the buffer/detergent method while the concentration and purity of the extracted DNA were 413.1±178 µg/mL and 1.82± 0.042 respectively in the salting-out method. Polymerase chain reaction was successful on extracted DNA with either method which proves the absence of inhibitors in the reaction. The electrophoresis results confirmed no breakage in either of the samples. The results of DNA extraction with buffer/detergent method showed that this method was safe, inexpensive and safe, and that the extracted DNA had high quantity and quality, therefore, this method is recommended as an appropriate method for DNA extraction from blood and semen samples in molecular laboratories.

The streptomycin regulatory gene, strR, from Streptomyces griseus, is a pathway specific regulator of streptomycin biosynthesis gene cluster. Here, two different sets of primers were designed (Oligo5) in order to amplify the strR. The gene was initially isolated from the Iranian strain of S. griseus (PTCC1127) and also the American strain ATCC1952. It was then confirmed as strR by semi-Nested PCR and RFLP PCR. The amplified gene (1134 bp) has two defined recognition sites for BamHI and XbaI. Therefore, it was cloned in E. coli, using a Streptomyces integrative specific vector pMA:hyg. The recombinant plasmid pSPstrR was then constructed and cloned in E. coli. The isolated strR gene was also cloned in E. coli, using the multi-copy and expression vector pBluescript in order to overproduce the StrR protein. The structures of these new constructs were also confirmed. The structural analyses of the new constructs were performed by gel electrophoresis and PCR. These vectors could be used for site directed mutagenesis, gene replacement and deletion strategies in Streptomyces griseus. Overproduced StrR protein could be used directly for early onset induction and overproduction of antibiotic.

The fecundity performance in sheep has been interesting for producers due to its economical importance. The estimated heritability for this trait is low (less than 10%) in various reports. However, the genetic gain from direct selection of this trait is greater than expected from infinitesimal theory base. Segregation of major gene/genes effective on prolificacy has been proposed as a main reason for this discrepancy. So far, mutations in some genes, all belonging to transforming growth factor b (TGF b), segregated in these flocks have been detected. The mutated genes in brief include: a) Booroola or Bone Morphogenetic Protein Receptor 1B (BMPR1-B) which is an autosomal gene with an additive effect on the ovulation rate and a partial dominance effect on litter size. b) Growth Differentiation Factor 9 (GDF9) which is another autosomal gene with an over-dominance effect so that homozygote mutant ewes are sterile. Eight mutations have been detected in this gene and the effect of each allele varies from 0.3 to 1.2 lambs per birth. c) Bone Morphogenetic Protein 15 (BMP15) is an overdominance sex-linked gene like GDF9. Ewes carrier for these fecundity genes keep their superiority over non-carrier ones in the whole life. Having mutations in two genes like BMP15 and BMPR-1B or BMP15 and GDF9 enhances the prolificacy compared to single mutation owners. To date, the presence of mutation in both BMP15 and GDF9 in Iranian sheep breeds have been confirmed. However, none of them are associated with a significant effect on prolificacy. The summation of single muations in each ewe might cause twining rate in these breeds. In this paper, we reviewd the history, mutations and the proposed action mechanism for these major genes.

For 50 years, the term “gene” has been synonymous with regions of the genome encoding mRNAs that are translated into protein. However, recent genome-wide studies have shown that the human genome is pervasively transcribed and produces many thousands of regulatory non-protein-coding RNAs including MicroRNAs, Small Interfering RNAs and Small Nucleolar RNAs, functional molecules that belong to small and long non-coding RNAs. According to recent studies, it is now clear that these RNAs play critical roles as transcriptional and post-transcriptional regulators, and are active in gene silencing and DNA demethylation. Evidence shows that intergenic regions are related with the expression of non-coding RNAs of complex diseases and their application, as a marker for diagnosis and treatment, is useful. These observations emphasize the need to move beyond the confines of protein-coding genes and highlight the fact that continued investigation of non-coding RNA biogenesis and function will be necessary for a comprehensive understanding of human diseases.

Salicylic acid plays a key role in plants defense against viruses. Induced systemic acquired resistance causes long lasting resistance to a wide range of pathogens including viruses. Salicylic acid can interfere in three main stages of virus pathogenicity cycle including replication, cell to cell movement and long distance movement. Transcriptional factors of TGA, MYB and WRKY families play a role in salicylic acid resistance to viruses. Salicylic acid induces expression of pathogenicity related proteins through a NPR1 dependent pathway in hypersensitive response and systemic acquired resistance. Independent signaling pathway of NPR1 is a different form of salicylilic acid dependent signal transduction which is required for specific resistance to plant viruses. Also, salicylic acid induces expression of RNA dependent RNA polymerase genes in Arabidopsis and Nicotiana plants which play an essential role in RNA silencing. Finally understanding of salicylic acid biology and its signaling pathways can increase resistance to stresses and product yield.

Beckwith-Wiedemann syndrome is a disorder characterized at birth by macrosomia, macroglossia, hypoglycemia and omphalocele. It is one of the causes of mental retardation. The gene is on the 11p15. We are reporting a 21-month-old boy with moderate mental retardation, a prominent occiput, macroglossia, crease of ear lobule and auricular pits. We believe that our patient is a new case of Beckwith-Wiedemann syndrome.

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system, with unknown etiology in which both genetic and environmental factors are thought to be involved. The human leukocyte antigen (HLA) system provides a set of genetic markers which lend themselves to systematic study. In Iran, HLA-A24, HLA-DR2, and HLA- DR15 are significantly increased in MS patients. The disease also has 3 main clinical presentations, consisting of relapsing- remitting (88%) primary progressive (7%) and secondary progressive with a gender ratio of 2.5:1 (female: male) and a mean age at onset of 27+ 7.4 years in our country. Five percent of our patients had a positive family history for the disease, 14% of patients had benign MS, and 12% with disease duration longer than five years had an Expanded Disability Status Scale <2. The opticospinal form of MS was not a common form of presentation of the disease in Iran.

Multiple odontogenic cysts, basal cell nevi and abnormalities in skeletal, nervous and endocrine systems characterize Gorlin-Goltz or nevus basal cell carcinoma syndrome. A 12-year-old patient with odontogenic keratocysts, multiple cryptic teeth in the jaw and in the cysts, multiple nevi on the skin, nail dyskeratosis and bone abnormalities is reported and literature review is presented in this paper.