Gene Mapping: Basics, Techniques and Significance.

Watson says, "Like the system of interstate highways spanning our country, the map of the human genome will be completed stretch by stretch". It may be possible to use genetic information to diagnose the disease accurately and to predict a patient's likely response to a particular medicine or treatment. For whole genome mapping development and application of mapping, sequencing and computational tools are very essential and also linkage, physical and sequence maps are required to put the information together. For most genome mapping projects involve markers consisting of a unique site in the genome and should be independent of any particular experimental resource. For mapping purpose the DNA and RNA identification is essential. These genes are identified by hybridizing DNA clones against Northern blot, cDNA libraries, Zoo blot, Western blot and Southern blot of genomic DNA digested with rare cutter restriction endonuclease. The various experimental studies of gene mapping have extended our understanding of the genetics. This has allowed the investigators to detect a particular gene, which is responsible for the disease. Recent studies have shown the various effective and scientific gene mapping techniques and gene identification methods, which are helpful to diagnose a particular disease. It is easy for the doctor to give right medicine to the right patient to cure the disease when he can identify the defective gene responsible for disease. This article reviews the details of identification techniques of genes, gene mapping with broad applications.

Screening of Epidermal Growth Factor Receptor Gene Mutation in Non-Small Cell Lung Cancer Using a PCR-Based Enzymatic Digestion Method

PURPOSE: We applied a simplified method using polymerase chain reaction (PCR)-based enzymatic digestion for the detection of epidermal growth factor receptor (EGFR) mutation. MATERIALS AND METHODS: We selected 74 samples of adenocarcinoma of the lung with EGFR exons 19 and 21 that had been previously sequenced. We designed PCR primers and chose a DNA restriction enzyme. Seventy four additional lung cancer samples were tested as a test set. For test sets, the PCR-based method was performed first, followed by validation of the result by DNA sequencing. RESULTS: In the first sample group, we found 15 (20.3%) mutations in exon 19, and 9 (12.2%) mutations in exon 21 using the sequencing method. By using the PCR-based method, we were able to identify all of the mutated samples detected by the sequencing method. The PCR-based method also detected mutations in exon 19 in three additional samples and in exon 21 in one additional sample. In the second sample group, by performing the PCR-based method, we found 10 (13.5%) and 7 (9.5%) mutations in exons 19 and 21, respectively. Additional mutations in exon 19 were identified in 2 samples by the sequencing method. However, the sequencing method failed to identify a mutation in exon 21 in one sample. CONCLUSION: The sensitivity of the PCR-based enzymatic digestion method seems to be comparable to that of the traditional sequencing method for detecting EGFR mutations. Our method can be widely used as a screening test to select patients who may benefit from EGFR targeted therapy.

Rapid identification of filamentous fungi by colony PCR / 中华皮肤科杂志

Objective To estimate the application value of colony PCR in the detection of pathogenic filamentous fungi. Methods Colony PCR was established and performed to amplify the internal transcribed spacer (ITS) region of 19 species (strains) of filamentous fungus followed by sequencing analysis. At the same time, DNA extracts from 8 of the 19 species of filamentous fungus were subjected to conventional PCR. Hha I and Hinf I endonucleases were used for restriction fragment length polymorphism (RFLP) analysis of the conventional and colony PCR products. Comparison analysis was carried out between the colony and conventional PCR. Results Of the 19 strains, 16(84.2%) yielded positive results by colony PCR; sequence analysis of the PCR products of ITS region revealed a 96% - 100% similarity with the reference sequence (NCBI database)of corresponding fungi. The amplification product length and RFLP profile of these products from the 8 species of filamentous fungus, except for those from Aspergillus nidulans, were consistent between the colony and conventional PCR. Conclusions Compared with conventional PCR, colony PCR-based detection of filamentous fungi is easy to operate, time and labor-saving, with high accuracy and reliability, and can be applied to the rapid identification of filamentous fungi.

The study of voltage-gated sodium channel subtype mRNA in spontaneously epileptic rat brain / 中华神经科杂志

0.05). But typeⅢsodium channel expressed higher than that in control groups in hippocampus, restriction mapping analysis showed thatⅢN increased significantly (P