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Genetic disorders 1


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Genetic Disorders (No 1)

Genetic Disorders (No 1)

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  • 1.  
  • 2. GENETIC DISORDERS (Introduction)
    • Dr. Shahab Riaz
  • 3.  
  • 4. Chromosome:
    • Greek ( chroma , color) and ( soma , body) bcz strongly stained by particular  dyes
    • organized structure of  DNA  and  protein , found in  cells
    • single piece of coiled DNA containing many  genes ,  regulatory elements  and other  nucleotide sequences
    • In eukaryotes, nuclear chromosomes are packaged by proteins into a condensed structure called  chromatin
    • very long DNA molecules to fit into the  cell nucleus
  • 5.  
  • 6. Gene:
    • basic unit of  heredity  in a living  organism
    • information to build and maintain the  cells  and pass genetic  traits  to offsprings
    • In general terms, a gene is a segment of  nucleic acid  that, taken as a whole, specifies a trait
  • 7.  
  • 8.
    • Gregor Mendel
  • 9. History:
    • Gregor Mendel  (1822–1884) a priest  and scientist
    • In 1860s, studied inheritance in  pea plants father of  genetics  for his study of the  inheritance  of certain traits  in  pea  plants
    • hypothesized  a factor that conveys traits from parent to offspring
    • over 10 years of his life on one experiment
    • showed that the inheritance of these traits follows particular  laws
    • Mendel's work was not recognized until the turn of the 20th century
    • Didn’t use the term  gene , explained results in terms of inherited characteristics
    • dominant  and  recessive  traits, the distinction between a  heterozygote and  homozygote ,  genotype  and  phenotype
  • 10. Deoxyribonucleic acid (DNA):
    • nucleic acid  
    • genetic  instructions & the long-term storage of  information
    • blueprints , or a  code for development and functioning
    • Construction of cellular proteins  and  RNA  molecules
    • DNA segments that carry this genetic information are called  genes
  • 11. DNA Structure:
    • two long  polymers  of simple units called  nucleotides
    • backbones made of  sugars  and  phosphate  groups joined by  ester  bonds
    • two strands are anti-parallel
    • Attached to each sugar is one of four types of molecules called  bases
    • sequence of these four bases along the backbone that encodes information
  • 12.  
  • 13.  
  • 14.  
  • 15. Messenger ribonucleic acid (mRNA) :
    • molecule of  RNA  encoding a chemical "blueprint" for a  protein  product
    • mRNA is  transcribed  from a  DNA  template
    • carries coding information to the sites of  protein synthesis : the ” ribosomes ” on RER
    • the nucleic acid polymer is  translated  into a polymer of  amino acids : a “ protein”
    • In mRNA as in DNA, sequence of  nucleotides  arranged into  codons  consisting of three bases each
    • Each codon encodes for a specific  amino acid
    • stop codons  terminate protein synthesis
  • 16.
    • Codon:
    • Base triplet in mRNA transcribed by DNA
    • If the base triplet in the DNA sequence is GCT Then
    • corresponding codon on the mRNA strand will be CGA
    • Transfer RNA (tRNA):
    • mediates recognition of the codon
    • provides the corresponding amino acid
    • Ribosomal RNA (rRNA):
    • central component of the ribosome's protein manufacturing machinery
    • Anti-Codon:
    • sequence of three adjacent nucleotides in transfer RNA
    • binds to a corresponding codon in messenger RNA
    • designates a specific amino acid during protein synthesis
  • 17.  
  • 18.  
  • 19.
    • 20 Amino Acids In Human Protein: Table of DNA Base Triplets, RNA Codons & Anticodons
  • 20. GENETICS:
    • Ancient Greek   genetikos , “genitive” and that from  genesis , “origin”
    • science  of  heredity  and  variation  in living organisms
    • living things inherit traits from their parents  prehistoric  times  improve crop plants and animals through selective breeding
    • Modern genetics basis by Gregor Mendel
  • 21.
    • Genome:
    • full set of chromosomes  or genes in a  gamete
    • So a regular  somatic cell  contains two full sets of genomes
    • In  haploid   organisms , including  bacteria ,  viruses , and  mitochondria , a cell contains only a single set of the genome
    • Genomics:
    • study of the  genomes  of organisms
    • entire  DNA sequence  of organisms and fine-scale  genetic mapping  efforts
    • Research of single genes does not fall into the definition of genomics
  • 22. Importance of Genetics
    • Life time frequency  670/1000
    • Classic genetic diseases + CVS diseases and cancer
    • Some diseases have both environmental + genetic role (atherosclerosis / HTN)
    • In medical practice  Iceberg of Genetic diseases  less severe
    • 50% of spontaneous abortions  gross chromosomal abnormalities
  • 23. Importance of Genetics
    • 100,000 previously thought but actually approx 30,000
    • Different combinations  > 100,000 proteins
    • Fully formed proteins can be sliced/stitched  > peptides than expected
    • Avoiding intra-uterine diseases
    • Thalassemia  inter-marriages
    • Treatments of cancer  Genetic Level
  • 24. Interesting Fact
    • 99.9% of genomic DNA sequence of any two humans is the same
    • 0.1% rest of the genome  accounts for the differences in features  approx. 3 million base pairs
  • 25. Genetic Advancements
  • 26. Molecular Basis of Human Diseases
    • Two general strategies used to isolate involved genes
    • Functional Cloning or Classical Approach:
    • Abnormal gene product / protein known
    • Isolate normal gene and clone
    • Determine molecular changes causing the disorder
    • Positional Cloning or Candidate Gene Approach:
    • In some diseases, multiple genes involved or no clue of defective product
    • Ignores the phenotype or protein product
    • Instead mapping disease phenotype to specific chromosome location
    • Marker genes identified  Close proximity to disease locus
    • Localized narrow limits  clone DNA from relevant site in vitro
    • Identification of protein  aberrant protein encoded by mutant genes
  • 27.  
  • 28. Genetic Engineering
    • Production of human biologically active agents
    • Recombinant DNA technology
    • Improving crop technology
    • manufacture of synthetic human  insulin  through the use of modified  bacteria
    • manufacture of  erythropoietin  in hamster  ovary cells
    • Growth hormone
    • GM-CSF & G-CSF
  • 29. Genetic Engineering
    • Isolation of the genes of interest
    • Insertion of the genes into a transfer  vector
    • Transfer of the vector to the organism to be modified
    • Transformation of the cells of the organism
    • 5. Selection of the genetically modified organism (GMO) from those that have not been successfully modified
  • 30.  
  • 31. Gene Therapy
    • insertion of  genes  into an individual's  cells  and  tissues  to treat a  disease
    • hereditary disease  in which a deleterious  mutant   allele  is replaced with a functional one
    • Although the technology is still in its infancy, it has been used with some success.
    • Appropriate Vectors ???
    • Random Insertion in other Cells
  • 32.