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Are identical twins identical in every cell?

Identical twins begin with a shared developmental origin, but their cells keep dividing. Genetic changes can arise during those divisions and enter different cell lineages. Researchers can compare sampled DNA to investigate that history. Differences in DNA sequence, differences in gene activity, and differences in experience are separate explanations, even when they all contribute to how two people differ.

3–7 min

Questions you could explore

  • What could DNA from one tissue tell you, and what would it leave unknown about the rest of the body?

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Health and the body

How does daylight set the body’s clock?

Feeling sleepy at night involves more than counting the hours since you woke up. Internal daily rhythms respond to outside cues, with light helping coordinate the body's sense of time.

3–5 min

How does daylight set the body’s clock?

Health and the body3–5 minFeeling sleepy at night involves more than counting the hours since you woke up. Internal daily rhythms respond to outside cues, with light helping coordinate the body's sense of time.

Health and the body

How does a vaccine give the immune system a memory?

The immune system can respond differently to something it has encountered before. Vaccines make use of recognition and memory, though different vaccine types introduce the relevant information in different ways.

4–5 min

How does a vaccine give the immune system a memory?

Health and the body4–5 minThe immune system can respond differently to something it has encountered before. Vaccines make use of recognition and memory, though different vaccine types introduce the relevant information in different ways.

Health and the body

Why won’t an antibiotic treat a viral cold?

The word infection covers illnesses caused by very different organisms. An antibiotic that helps against certain bacteria has no matching target in the viruses that cause a cold.

2–3 min

Why won’t an antibiotic treat a viral cold?

Health and the body2–3 minThe word infection covers illnesses caused by very different organisms. An antibiotic that helps against certain bacteria has no matching target in the viruses that cause a cold.

Are identical twins identical in every cell? | Speech Topic | speaking.app