ノックアウトマウスという言葉を聞いたことがありますか？これは科学の世界で非常に重要な役割を果たす特別なマウスです。このレッスンでは、なぜノックアウトマウスが重要なのか、どのように作られるのか、どんな病気の研究に使われているのかを、やさしい言葉で解説します。遺伝子と病気のつながりに興味がある人には、ぴったりの内容です。

要約

ノックアウトマウスとは、特定の遺伝子を取り除いたマウスで、遺伝子の機能を調べるために使われます。この動画では、ノックアウトマウスの作り方、ホモ接合性、キメラマウス、CFTR遺伝子と嚢胞性線維症の例、そしてCRISPR-Cas9による最新の遺伝子編集法について紹介されています。また、この技術の限界や、他の動物モデル（ハエ、線虫、魚）への応用についても触れています。ノーベル賞を受賞した研究としても知られています。生物学や医学研究に興味がある人に最適な教材です。

以下は英語の授業で教えた内容を一部修正し、日本語を中心にウェブレッスン用に再構成したものです。授業ではすべて英語で進行しましたが、ここでは主に日本語で説明しています。

CEFRとTOEICレベル – CEFR and TOEIC LEVEL & RATIONALE

このスクリプトは CEFR B2レベル で、TOEICスコアで言うと785～940点 に相当します。
このレベルでは、専門的なトピックや複雑な文、学術的な説明も理解できる力が求められます。
B1レベルやTOEIC600点前後の学習者にとっては、サポートなしでは少し難しいかもしれません。

ESL学習目標 – ESL LEARNING OBJECTIVES
• 遺伝子と生物学に関する語彙を習得する
Learn vocabulary related to genes and biology
• 説明的な文の構造を理解する
Understand how explanatory sentences are structured
• 動画から主要な情報を聞き取る力を養う
Develop ability to extract key ideas from videos
• 科学的なプロセスを英語で説明する練習をする
Practice explaining scientific processes in English

その他の学習目標 – OTHER LEARNING OBJECTIVES
• 科学と社会のつながりを考える
Reflect on the relationship between science and society
• 医学研究の倫理や限界について考察する
Consider the ethics and limitations of medical research

効果的な動画視聴方法 – WATCHING STRATEGY TIP
1回目は全体の流れをつかみ、2回目でキーワードや専門用語をチェックしてみましょう。
Watch once for general understanding, then again to focus on keywords and terminology.

視聴前の質問 – PRE-WATCH QUESTIONS

  1. What do you think a “knockout mouse” is used for in science?
    ノックアウトマウスは科学で何に使われていると思いますか？
  2. Do you know any diseases that are caused by gene problems?
    遺伝子の問題で起こる病気を知っていますか？

動画をよく見てから、質問に答えてみてください。2回見ると理解しやすくなるかもしれません。（授業ではスクリプトも配布されています。）

内容理解問題– COMPREHENSION QUESTIONS

  1. What is a knockout mouse?
  2. Why are knockout mice useful for studying genes?
  3. What kind of cells are used to make a knockout mouse?
  4. What is homologous recombination used for in this process?
  5. What are chimeric mice?
  6. How do scientists create homozygous knockout mice?
  7. What disease was one of the first to be studied using knockout mice?
  8. What is one advantage of using CRISPR-Cas9?

正誤問題– TRUE / FALSE

  1. Knockout mice have extra genes added.
  2. Scientists use embryonic stem cells to begin the process.
  3. Homologous recombination adds a new gene to the DNA.
  4. Chimeric mice have both edited and unedited tissues.
  5. Homozygous means the gene is still present.
  6. Knockout mice helped study cystic fibrosis.
  7. CRISPR-Cas9 can edit multiple genes at once.
  8. All genes can be safely removed from mice.
  9. Humans and mice share 85% of protein-making genes.
  10. Knockout mouse research won a Nobel Prize.

遺伝子研究者への質問 Questions for a Genetic Researcher

  1. What tools do you use to edit genes?
  2. How do you decide which gene to study?
  3. What are the challenges in creating knockout animals?
  4. How do you ensure ethical research with animals?
  5. What diseases are you currently investigating?
  6. Have knockout mice helped your work directly?
  7. What is the future of gene editing?
  8. What other animals do you work with?

重要語句リスト – GLOSSARY

EnglishSimple DefinitionExample SentenceJapanese Translation
genepart of DNA that controls traitsA gene decides your eye color.遺伝子
knockout mousea mouse with one gene removedScientists study disease with a knockout mouse.ノックアウトマウス
stem cella basic cell that can become many typesStem cells can grow into brain or skin cells.幹細胞
embryoearly stage of lifeThe embryo grows inside the mother.胚
homologous recombinationa way to swap DNA partsScientists used homologous recombination to remove the gene.相同組換え
chimericmade of two types of cellsChimeric mice have both edited and normal cells.キメラの
mutationa change in DNAThis disease is caused by a mutation.突然変異
CFTR genegene linked to cystic fibrosisThe CFTR gene is missing in some knockout mice.CFTR遺伝子
cystic fibrosisa disease affecting lungsCystic fibrosis causes thick mucus in the lungs.嚢胞性線維症
preciseexact and clearThe CRISPR method is very precise.正確な
homozygousboth gene copies are the sameA homozygous knockout has no working copy of the gene.ホモ接合の
heterozygoushaving one gene copy missingThe first generation was heterozygous.ヘテロ接合の
embryonicrelated to embryosEmbryonic cells grow fast.胚の
immune systemthe body’s defense systemYour immune system protects you from sickness.免疫システム
CRISPR-Cas9a tool to cut and change DNACRISPR-Cas9 changed the gene in the mouse.CRISPR-Cas9

句動詞・前置詞動詞リスト – PHRASAL / PREPOSITIONAL VERBS LIST

• take away – remove – 取り除く

  1. Scientists took away the gene to see what happens.
    科学者は何が起こるか見るために遺伝子を取り除きました。
  2. They took away one part of the code.
    コードの一部を取り除きました。

• lead to – cause, result in – 〜につながる

  1. Removing the gene led to a new discovery.
    遺伝子を除去したことで新しい発見につながりました。
  2. This mutation can lead to disease.
    この突然変異は病気につながる可能性があります。

• make up – consist of – 〜で構成される

  1. The chimera is made up of different animal parts.
    キメラは異なる動物の部分で構成されています。
  2. Our DNA is made up of many genes.
    私たちのDNAは多くの遺伝子でできています。

文法のポイント – GRAMMAR FOCUS

  1. Passive Voice – 受け身形
    英語では、動作の受け手を主語にすることで、フォーマルで説明的な文が書けます。
    In English, the passive voice focuses on the action receiver. Useful in science.

Example Sentences:

  1. The CFTR gene was removed to study its role in disease.
  2. The mouse was implanted with edited stem cells.

練習問題: Fill in the blanks with the correct passive form.

  1. The gene ______________ (remove) from the cells.
  2. The mice ______________ (use) in many studies.
  3. A new method ______________ (develop) recently.
  4. Symptoms ______________ (observe) in the mouse.
  5. The cells ______________ (insert) into the embryo.
  6. The gene ______________ (replace) with a mutation.
  7. The embryo ______________ (implant) in the mouse.
  8. The method ______________ (call) homologous recombination.

Relative Clauses – 関係詞
関係詞で説明を追加することで、複雑な情報も明確に伝えられます。
(Relative clauses add extra information about a noun.)

練習問題: Combine the sentences using “which” or “that.”

  1. This is the gene. It causes disease.
  2. We studied a method. It is called CRISPR.
  3. She works with mice. The mice are chimeric.
  4. This is the tool. It edits DNA.
  5. I watched a video. It was interesting.
  6. This is a disease. It affects the lungs.
  7. That is the mouse. It had no gene.
  8. These are the steps. They are important.

発音のポイント – PRONUNCIATION TIP
Practice the soft “ch” sound in “chimeric” – it sounds like /k/ in this word, not /ch/ as in “cheese.”

発展問題– EXTENSION QUESTIONS

  1. How do you feel about using animals in scientific research?
  2. Should gene editing be used in humans? Why or why not?
  3. What other areas might benefit from knockout technology?
  4. Do you think technology like CRISPR should be freely available?
  5. How would you explain a “knockout mouse” to a friend?
  6. What are some other famous uses of mice in science?
  7. If you could remove a gene from a plant, what would you want to change?
  8. What are some dangers of changing genes?

実践課題 – PRACTICAL APPLICATION TASK

Explain the knockout mouse process to a classmate using simple steps. Try to draw a diagram to help them understand.

ライティング課題 – WRITING TASK

In about 60 words, describe how CRISPR has changed the way we study genetics. Mention at least one benefit and one challenge of this method.

生物学や医学英語を楽しく学びたい方は、ぜひNatural English英会話教室のレッスンに参加してみてください！見学・体験レッスンも受付中です！

内容理解問題の解答（タイムスタンプ付き）– ANSWERS WITH TIMESTAMPS

  1. A knockout mouse is a mouse with a gene removed. (0:32-0:57)
  2. It helps show what a gene does by removing it. (0:47)
  3. Embryonic stem cells. (1:03)
  4. To swap out or disable a gene. (1:34)
  5. Mice with some tissues having the removed gene. (2:10)
  6. By breeding heterozygotes until both gene copies are gone. (2:50)
  7. Cystic fibrosis. (3:31)
  8. It is faster, more precise, and can target multiple genes. (4:04–4:40)

正誤問題の解答 – TRUE / FALSE ANSWERS

  1. F 2. T 3. F 4. T 5. F 6. T 7. T 8. F 9. T 10. T


ライセンス情報 – SOURCE LICENCE NOTE
This video is used under YouTube’s standard embedding permissions for educational purposes.