What is DNA?DNA= Deoxyribu-Nucelic Acid• DNA is a very large molecule, made upof smaller units called nucleotides• Each nucleotide has three parts: asugar (ribose), a phosphate molecule,and a nitrogenous base.• The nitrogenous base is the part of thenucleotide that carries geneticinformation• The bases found in DNA are four:adenine, cytosine, guanine, andthymine ( ATP, CTP, GTP, and TTP)
What is gene?• A gene is a stretch of DNAthat codes for a type ofprotein that has a function inthe organism.• It is a unit of heredity in aliving organism.. All livingthings depend on genes• Genes hold the informationto build and maintain anorganisms cells and passgenetic traits to offspring.
What are gene components?• Genes contain:EXONS: a set of coding regions…INTRONS: Non-coding regions removed sequenceand are therefore labeled split genes (splicing).
What is the genome?• The geneticcomplement of anorganism, includingall of its GENES, asrepresented in itsDNA
What is the gene expression?• Is the process by whichinformation from a gene isused in the synthesis of afunctional gene product (proteins)• The process of geneexpression is used by allknown life - eukaryotes ,prokaryotes , and viruses - togenerate the macromolecularmachinery for life.
Steps of gene expression• (1) Transcription (mRNAsynthesis),• (2) Post-transcriptionalprocess (RNA splicing),• (3) Translation (proteinsynthesis)• (4)post-translationalmodification of a protein.
What are the genetic changes?• An alteration in a segment ofDNA, which can disturb agenes behavior andsometimes leads to disease.• It may be:• (1) Small genetic change,genetic drift (mutation)• (2) large genetic change,genetic shift (recombination)
What is mutation?• Are changes in theDNA sequence of acells genomecaused byradiation, viruses,transposons andmutagenicchemicals,
What is recombination?• The exchange ofcorresponding DNAsegments betweenadjacent chromosomesduring the special typeof cell division thatresults in theproduction of newgenetic make up...
Recombinant DNAtechnologyIn vitro recombinationGenetic engineeringGenetic surgery
In genetic engineering,recombination can alsorefer to artificial anddeliberate recombinationof pieces of DNA, fromdifferent organisms,creating what is calledrecombinant DNA.
Application of geneticengineering in Medicine(1) Treatment ofgenetic diseases(gene therapy)• e.g. SCID girl
(2) Production ofmedically usefulbiologicals (e.g.insulin)Recombinant Human Growth HormoneRecombinant insulin (Humulin)
(3) Vaccines production• Firstly, the gene in apathogenic virus thatstimulates protective immunityshould be identified.• That portion of DNA is thenisolated and incorporated intoan established harmless virus(e.g. vaccinia virus).
• This new recombinant virus isused as a vaccine.• These vaccines are much safersince they do not expose thepatients to the actual virus anddo not risk to infection.• This method may be useful invaccines against malaria andschistosomiasis and manyviruses (e.g. HBV)
(4) PharmacogenomicsDeals with the influenceof genetic variation ondrug response in patientsby correlating geneexpression with a drugsefficacy or toxicity
Design drugsadapted to anindividualsgenetic make-up
• Write in details about the medicalapplications of recombinant DNAtechnology
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