Principles and tools of genetic technology
Introduced| English | Meaning |
|---|---|
| genetic engineering/dʒɪˈnetɪk ˌendʒɪˈnɪərɪŋ/ | The deliberate alteration of genetic material using biotechnology, such as inserting, removing or editing DNA. |
| recombinant DNA/ˌriːˈkɒmbɪnənt ˌdiː en ˈeɪ/ | DNA joined from two sources. |
| reverse transcriptase/rɪˈvɜːs trænˈskrɪpteɪs/ | Makes DNA from an mRNA template. |
| plasmid/ˈplæzmɪd/ | A DNA ring used as a vector to carry the gene into a cell. |
| vector/ˈvektə/ | An organism or carrier that transfers a pathogen or genetic material to another cell or organism. |
| restriction endonuclease/rɪˈstrɪkʃn ˈendəʊnjuːklɪeɪs/ | Cuts DNA at a specific sequence, leaving sticky ends. |
| sticky ends/ˈstɪki endz/ | Short single-stranded DNA overhangs that can pair with complementary overhangs. |
| promoter/prəˈməʊtə/ | promoter |
| marker gene/ˈmɑːkə dʒiːn/ | A gene whose detectable effect helps identify cells or organisms carrying particular genetic material. |
| gene editing/dʒiːn ˈedɪtɪŋ/ | A precise form of genetic engineering. |
Genetic engineering 基因工程
- Recombinant DNA 重组DNA is DNA joined from two different sources.
- Genetic engineering deliberately changes an organism's genes — often by transferring a gene so it is expressed.
- It uses a clever toolkit of enzymes and carriers.
Recombinant DNA is:
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Recombinant DNA combines DNA from two sources — e.g. a human gene joined into a bacterial plasmid.
Recombinant DNA is made by joining DNA from two different sources (e.g. a human gene into a bacterial plasmid).
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Because the genetic code is universal, a human gene works inside a bacterium that takes it up.
Getting the gene
The gene to transfer can be obtained by:
- cutting it out of a donor's DNA,
- making it from mRNA using reverse transcriptase 逆转录酶,
- building it chemically from nucleotides.
A gene inserted into a plasmid 质粒 vector 媒介 and taken up by a bacterium
The tools of genetic technology
Genetic engineering moves a useful gene into another organism so it makes a desired protein.
Reverse transcriptase is used to:
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Reverse transcriptase builds a DNA copy from mRNA — one way of obtaining the gene to transfer.
The tools
| Tool | Role |
|---|---|
| restriction endonuclease 限制性内切酶 | cuts DNA at a specific sequence, leaving sticky ends 黏性末端 |
| DNA ligase | joins DNA pieces together |
| plasmid | a DNA ring used as a vector to carry the gene into a cell |
| reverse transcriptase | makes DNA from an mRNA template |
- A promoter 启动子 (the "switch") must go in too, or the gene stays silent.
- A marker gene 标记基因 (e.g. one that glows) shows the transfer worked.
Which tool cuts DNA, leaving "sticky ends"?
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Restriction enzymes cut at specific sequences leaving sticky ends; ligase then joins matching ends.
A plasmid is used in genetic engineering as a:
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The plasmid is a cloning vector: the gene is joined into it and the recombinant plasmid is taken up by a cell.
A gene that shows (e.g. by glowing) which cells took up the new gene is a ______ gene.
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A marker gene (e.g. coding for a fluorescent product) reveals which cells were successfully transformed.
Match each tool to its job.
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Cut with restriction enzymes, join with ligase, carry with a plasmid vector; reverse transcriptase makes the gene from mRNA.
Gene editing 基因编辑
- Gene editing is a precise form of genetic engineering.
- It inserts, deletes or replaces DNA at an exact site in the genome.
You've got it
- recombinant DNA = DNA joined from two sources; genetic engineering transfers a gene to be expressed
- get the gene by cutting it out, reverse transcriptase (from mRNA), or synthesis
- tools: restriction enzyme (sticky ends), ligase (join), plasmid vector, plus a promoter + marker gene
- gene editing = precise insert/delete/replace at an exact site