Скачать с ютуб First DNA genome ever sequenced: Overlapping genes and more in the PhiX174 genome в хорошем качестве

First DNA genome ever sequenced: Overlapping genes and more in the PhiX174 genome

Nucleotide sequence of bacteriophage phi X174 DNA. Sanger F, Air GM, Barrell BG, Brown NL, Coulson AR, Fiddes CA, Hutchison CA, Slocombe PM, Smith M. Nature. 1977 Feb 24;265(5596):687-95. doi: 10.1038/265687a0. OTHER VIDEOS YOU MIGHT LIKE: • The genetic basis of sickle cell anemia: Why I want to join the HbA-Team -    • The genetic basis of sickle cell anem...   • The discovery of recombinant DNA technology (and what we can learn from it) -    • The discovery of recombinant DNA tech...   • The secrets of the tea tree genome: How they determine qualitea, varietea & adaptabilitea! -    • The secrets of the tea tree genome: H...   In the year 1977 Sanger and his team sequenced the entire length of a viral genome, PhiX174. It is a class of bacteriophage whose genome has a closed single stranded DNA structure. It was also the first ever whole genome to be sequenced. By taking insights from prior studies on sequencing the virus, they performed the plus and minus method of sequencing. DNA polymerase extends the primer and makes complementary copies of the virus template in the presence of dNTPs one of them being radioactively labelled. This helps visualise the different products on the gel. The minus system uses three dNTPs such that the synthesis stops at the point where the missing dNTP had to be present, the plus system on the other had uses only 1 dNTP and synthesis will stop where that particular dNTP is located. The products were further analysed by electrophoresis on acrylamide gel. And by this method the whole length of the genome was sequenced which in turn decoded many important locations and characteristics including the various transcription start sites of the genes as well as translation initiation and termination sites of all the proteins encoded by them. A number of methods were used to identify these sites including the presence of a known promoter sequence or the presence of a ribosomal binding site which favoured for the identification of the required codon or sequence(s) and their respective locations. The striking feature of the virus is the synthesis of a greater number of amino acids than the number of nucleotides it contains. Considering which, the virus has economised its genome structure with respect to arrangements of genes by the overlapping or gene within gene property. Two genes can share the same/different reading frames in this case to code for their proteins. This aspect of study encouraged the genome sequencing of many infectious pathogens which potentially revealed the exact cause of the disease they render. Thus, bringing a tremendous breakthrough in the field of medical science for developing and improving treatment and diagnostic procedures. Not only medicine other departments of science have also been benefitted by this study. Creator: Parinitha Vijaygopal References: Sanger F, Air GM, Barrell BG, Brown NL, Coulson AR, Fiddes CA, Hutchison CA, Slocombe PM, Smith M. Nucleotide sequence of bacteriophage phi X174 DNA. Nature. 1977;265(5596):687-695. Schott H. Chemical synthesis of a phage-specific DNA fragment. Makromolek Chem. 1974;175(6):1683-1693 (1974). Sharma S, Chatterjee S, Datta S, Prasad R, Dubey D, Prasad RK, Vairale MG. Bacteriophages and its applications: an overview. Folia Microbiol (Praha). 2017;62(1):17-55. Pribnow D. Nucleotide sequence of an RNA polymerase binding site at an early T7 promoter. Proc Natl Acad Sci U S A. 1975;72(3):784-788. Sanger F, Coulson AR. A rapid method for determining sequences in DNA by primed synthesis with DNA polymerase. J Mol Biol. 1975;94(3):441-448.