Shadowing Practice: CONTEMPORARY TOPICS 2 UNIT 11 BIOLOGY DNA TESTING - Learn English Speaking with Video
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Hello.
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Today I'd like us to concentrate on DNA.
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We'll focus on DNA testing and specifically on DNA testing of people.
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Before I explain how it's done, I want to review a bit from the reading.
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Now, you'll recall that cells comprise every part of our body.
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Our DNA is in every cell.
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DNA contains genetic information like eye color, hair color, height, and many other traits passed down from a mother and a father to their child.
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So, each of us has our own DNA, our own combination of genetic information from our parents.
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For example, a brother and a sister may end up with the same color of eyes and hair.
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However, other genetic information received from the parents will be different, which is why they look different.
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For example, maybe the brother is short, like the mother, and the sister is tall, like the father.
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Keep in mind that DNA is in every cell in the body
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and that all of these cells contain the same genetic information.
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Now, let's look at how DNA testing is used to identify people.
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Scientists create a DNA profile, also called a DNA fingerprint.
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To do this, they need DNA from the person.
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They take samples from different parts of the body, like hair, blood, skin, fingernails, and body fluids.
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Next, they extract the DNA from the cells in these samples.
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Then, they read the DNA with a computer.
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They use the data to create the DNA fingerprint.
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Statistically, it's very unlikely that any two people will have identical fingerprints.
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Now, let's ask, how is DNA testing used?
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Well, there are many ways.
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For example, to identify an unknown accident victim, or to find out who the father of a child is.
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Now, here's an interesting one.
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In 1999, scientists used DNA testing to prove that the son of the French king,
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Louis XVI and Marie Antoinette, in fact, died in prison.
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He didn't escape as some people had believed.
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DNA testing identified the son's body.
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People have been arguing about this for more than two centuries.
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Another use of DNA testing is by police to solve crimes.
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For example, say there's a murder.
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The police have a suspect they think did it.
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in the crime lab, scientists use DNA samples from the suspect and DNA samples from the evidence at the crime scene.
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Then, they design what's called probes.
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When the probes are put in with the DNA samples from the suspect and the DNA samples from the evidence,
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the probes show if the two sets of samples match.
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DNA identification is very effective, but not 100% foolproof.
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For example, suppose the only evidence at the crime scene is blood from the suspect.
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If there's a match between a sample of the crime scene blood and the suspect's blood, this will help the police.
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However, a single match from just blood, in this case, isn't very strong evidence.
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In contrast, let's say the crime lab has four samples from the crime scene and four samples from the suspect.
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Hair, blood, fingernails, and skin samples.
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They design four probes, one for each sample, and they get four matches.
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Bingo!
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The police can now feel more confident that they have the right suspect.
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Why?
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Remember, I said DNA is in every cell in our body, and each cell contains all of our unique genetic information.
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Now, let's turn to how DNA testing is used in the medical field.
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Here, let's consider how genetics is being used to diagnose diseases.
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With diseases, most DNA tests are given for one of two reasons.
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either to find out if someone has a certain disease or to see if the person is at risk for developing it.
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Researchers have found more than 6,000 genetic disorders.
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A genetic disorder means something isn't normal in the person's genes, a mutation.
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A change in one gene can cause a disease
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and a DNA test can and show
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if someone has a mutation in a gene that puts them at risk for the disease.
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Notice, I'm not saying that a change in one gene will cause a disease, only that the risk is higher.
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We're learning more and more every day about genetic diseases.
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For example, it now appears that the disease Alzheimer's, which damages memory in older people, is linked to our genes.
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So, we have to ask, what are the pros and cons of DNA testing in medicine.
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On the positive side, testing might save lives.
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If a doctor can diagnose a disease in its early stages, the patient can get treated earlier.
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Or, if a couple wants to have a baby,
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they can use DNA testing to find out beforehand if any risks for problems or diseases exist.
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On the negative side, there's the issue of fairness.
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What happens if DNA testing reveals that we have a genetic disorder that could cause a disease, and that information becomes known?
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This brings us to some concerns about privacy.
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A DNA profile contains a lot of personal information.
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So I'd like you to think about the following questions.
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One, who should own the DNA fingerprint once it's made?
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Two, who should have access to it?
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3. How should genetic information be used? And 4.
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Would you want people, especially people you don't know, to have access to your DNA fingerprint?
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These are some of the ethical questions we face about how to use the scientific knowledge we have.
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So, please give these questions some thought as you review the lecture.
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That's all for now.
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Vocabulary and speaking notes for this lesson
This B2 speaking lesson is built on the video “CONTEMPORARY TOPICS 2 UNIT 11 BIOLOGY DNA TESTING”. The speaker keeps coming back to these words: Dna, sample, testing, genetic, disease. This video has 77 sentences and 920 words to shadow. The speech runs for 7:13. The speaker talks at a steady 128 words per minute, a comfortable pace for shadowing. 86% of the words are among the 3,000 most common in English; the rest is worth studying before you start.
Key vocabulary in this video
The 15 most advanced words in the video, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| fingerprint noun | /ˈfɪŋɡɚˌpɹɪnt/ | The natural pattern of ridges on the tips of human fingers, unique to each individual. |
| probe noun | /pɹoʊb/ | Any of various medical instruments used to explore wounds, organs, etc. |
| diagnose verb | /ˈdaɪ.əɡˌnoʊs/ | To determine which disease is causing a sick person's signs and symptoms; to find the diagnosis. |
| fingernail noun | /ˈfɪŋɡɚˌneɪl/ | The hard, flat translucent covering near the tip of a human finger, useful for scratching and fine manipulation. |
| mutation noun | /mjuˈteɪʃən/ | Any alteration or change. |
| foolproof adjective | /ˈfuːl ˌpɹuːf/ | Of a device: protected against, or designed to be proof against, misuse or error. |
| comprise verb | /kəmˈpɹaɪz/ | To be made up of; to consist of (especially a comprehensive list of parts). |
| beforehand adverb | /bɪˈfɔɹhænd/ | At an earlier or preceding time. |
| statistically adverb | /stəˈtɪs.tɪ.kə.li/ | In a statistical way. |
| trait noun | /tɹeɪt/ | An identifying characteristic, habit or trend. |
| bingo noun | /ˈbɪŋ.ɡoʊ/ | A game of chance for two or more players, who mark off numbers on a grid as they are announced by the caller; the game is won by the first person to call out… |
| fairness noun | /ˈfɛɚ.nəs/ | The property of being fair or equitable. |
| genetics noun | /dʒəˈnɛt.ɪks/ | The branch of biology that deals with the transmission and variation of inherited characteristics, in particular chromosomes and DNA. |
| researcher noun | /ˈɹiˌsɝ.t͡ʃɚ/ | One who researches. |
| extract noun | /ˈɛkstɹækt/ | Something that is extracted or drawn out. |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| find out verb | To discover, as by asking or investigating. |
| put in with verb | To commit to something with; to partner with. |
Pronunciation to watch
The speaker uses 10 contractions and reduced forms, such as I'd, isn't, didn't. Say them the short way, as you hear them.
- The “sh” and “zh” sounds: mutation /mjuˈteɪʃən/, identification /aɪˌdɛn(t)ɪfɪˈkeɪʃn̩/
- Long words — get the stress right: statistically /stəˈtɪs.tɪ.kə.li/, identification /aɪˌdɛn(t)ɪfɪˈkeɪʃn̩/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Shadow it sentence by sentence at normal speed, repeating each one until your rhythm matches the speaker.
- Record yourself and compare with the original, paying attention to words like fingerprint, probe, diagnose.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.