PROF. MADYA DR. KAMARUZAMAN MOHAMED (DR. KM)
[email protected] 019-472-6397 KANDUNGAN KURSUS / COURSE CONTENT • • • • • • • • •
BAHAN GENETIK / GENETIC MATERIALS STRUKTUR DAN KOMPOSISI KROMOSOM / CHROMOSOME STRUCTURE AND COMPOSITION PEREPLIKAAN DNA / DNA REPLICATION SINTESIS PROTEIN / PROTEIN SYNTHESIS PENGAWALATURAN GEN / GENE REGULATION MUTASI PERINGKAT DNA DAN KROMOSOM / DNA AND CHROMOSOMAL MUTATION STRUKTUR HALUS GEN / GENE FINE STRUCTURE PERWARISAN LUAR NUKLEUS / EXTRANUCLEAR INHERITANCE PENGENALAN KEPADA KEJURUTERAAN GENETIK / INTRODUCTION TO GENETIC ENGINEERING
GENETIC MATERIAL - INTRODUCTION Earlier thought – Protein is the genetic material •
Majority of cell content is protein - > 50% of dry weight
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Discovery of nuclein (Miescher – 1868) - contains P but no S, different from protein - tetranucleotide hypothesis (Levene – 1910) - too simple – not a big enough variation (1:1:1:1) - proven wrong by Chargaff (1940’s)
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Active research at the time - heredity and mutation
Genetic material should have the ability to: - store information - pass the information to the offspring - dissipate the information when needed - vary via mutation
Experiments Leading to the Discovery that DNA and RNA are the Genetic Material A.
Direct evidence in prokaryote: 1. Frederick Griffith (1927) – transformation 2. Oswald Avery, Colin MacLeod and Maclyn McCarty (1944) – enzyme digestion and transformation 3. Alfred Hershey and Martha Chase (1952) – reproduction of phage T2 during infection of E. coli 4. Heinz Fraenkel-Conrat and B. Singer (1957) - TMV 5. John Spizezen dan Dean Fraser (1957) – initiate phage infection with disrupted T2 particles on bacterial spheroplast 6. George Guthrie dan Robert Sinsheimer (1960) – transfection of E. coli spheroplast with purified DNA resulted in production of complete ΦX-174 bacteriophages
B. Direct evidence in eukaryote: 1. Recombinant DNA Technology – expression of eukaryotic genes in bacteria 2. Transgenic animals – human β-globin gene in fertilised mice egg, shown to be maintained in adult mice tissue and can be inherited to the mice progeny C. Indirect evidence in eukaryote and prokaryote: 1. Correlation between ploidy level of cells the amount of DNA present (number of chromosomes) 2. Presence of DNA in organelles 3. Mutagenesis - absorption vs action spectrums
CIRI-CIRI BAHAN GENETIK 1. Keupayaan menyimpan maklumat kestabilan fizikal dan kimia DNA vs RNA keadaan berheliks molekul hidrofobik selain timina yang membentuk urasil melalui pendeaminan 9. Keupayaan untuk memperturunkan/mewariskan maklumat -
proses pereplikaan meiosis
3.
Keupayaan untuk menyebarkan maklumat bila-bila perlu - melalui pengekspresan gen - isyarat permulaan, penamatan dan berapa amaun perlu - jujukan asid amino dalam protein
4.
Keupayaan bervariasi melalui mutasi (dua mekanisme utama) - pertukaran kimia ke atas bes-bes yang mewujudkan sifat pengikatan hidrogen baru dan menyebabkan bes baru hadir dalam molekul yang baru direplikakan - kesilapan pereplikaan di mana bes-bes salah atau bes berlebihan/berkurangan disisipkan ke dalam molekul baru