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Ch.9 DNA-Based Information Technologies, DNA analysis methods -Polymerase…

- - - - To mutate an amino acid, change the nucleotide(s) in
        the coding DNA and express the mutated gene.
      - Site-directed mutagenesis usually relies on chemically synthesized mutated primers that are incorporated into newly synthesized DNA.
    - - Humans have short sequences that repeat next to each other.
        — short tandem repeats (STR)
      - Differences in the number of repeats cause variations in the
        length of fragments
      - Allows matching "suspect" samples to known individuals
      - 13 well-studied locations are used in identifications.
  - - - used to convert RNA code to cDNA and amplify specific segments
      - :star: mRNA is intron-free genetic material, as the codons have already been spliced out.
      - 用鹼把 mRNA (AAAA......) 去掉，因為mRNA在鹼中不穩定
    - - used to show quantitative differences in gene levels
- - - - Cleave DNA phosphodiester bonds at specific sequences
      - Common in bacteria
      - Some make staggered cuts.
        
        sticky ends
      - Some make straight cuts.
        
        blunt ends
    - - Human DNA ligase uses ATP.
      - Bacterial DNA ligase uses NAD.
  - - - Antibiotics, such as penicillin and ampicillin, kill bacteria.
      - Plasmids can carry genes that give a host bacterium a resistance against antibiotics.
      - Allows growth (selection) of bacteria that have taken up the plasmid
    - - 2步驟確認 :
        :!:plasmid 是否塞進去
        :!!:塞進去的 plasmid 是否含目標DNA片段
- - - - similar to using plasmids.
      - Often, a colorimetric approach using X-gal is employed to select for colonies containing the chromosomal insert.
      - Plates also contain X-gal,
        a substrate for β-galactosidase that yields a blue product.
        
        :star: cam : 檢測 vector 有無存在
        :fire: X-gal : 檢測 LacZ 有無被打斷
        
        lacZ gene
        (required for the production of the enzyme β-galactosidase)
    - - Yeast are the simplest eukaryote for DNA recombination.
      - They have linear chromosomes with telomere端粒（真核生物染色體末端的DNA重複序列）ends, which can be unstable in vitro體外.
      - YAC is circular to accommodate quick replication and stable storage
        but has a removable segment that linearizes the product for transformation.
- - - - 一抗接在抗原上，含螢光基因的二抗再接在一炕上