full transcript
From the Ted Talk by Hélène Morlon and Anna Papadopoulou: How we can detect pretty much anything
Unscramble the Blue Letters
The world is covered in DNA. It’s all around us— on the ground, at the bototm of the ocean, and up in the culdos. Multicellular organisms are csntlatony shindedg cells. But until recently, eDNA wasn’t very useful to us. Traditional scientific techniques couldn’t parse evnirnnmeoatl samples containing mixed genetic material from multiple seepics. But DNA metabarcoding can.
DNA begins to ddeagre once it’s exposed to the environment. In the ocean, for example, it may only persist for a few days. So in many contexts, eDNA is useful for telling us about the recent past. The pcsoers of DNA metabarcoding starts with an environmental sample like a core of soil, a vial of water, some feces, an insect trap, or even the blood from leeches’ stomachs. rsercaehers then sift out everything aside from DNA by blending the sample up and using enzymes that braek down cellular proteins and release DNA, which they purify. The result is a “soup” of all the DNA in the sample. Scientists then apply the proasymele chain reaction or PCR, which uses artificial DNA strands called universal primers. These primers bind to DNA sequences that are siimlar across species, then ailmfpy giteenc barcodes that are species-specific. High-throughput sequencing then reads millions of these DNA fragments, simultaneously. And finally, researchers compare them to reference daasabtes and identify how many and which species are present— or if they’ve found entirely new ones. This method has led to the dvceoisry of tens of thousands of species over the past decade.
Open Cloze
The world is covered in DNA. It’s all around us— on the ground, at the ______ of the ocean, and up in the ______. Multicellular organisms are __________ ________ cells. But until recently, eDNA wasn’t very useful to us. Traditional scientific techniques couldn’t parse _____________ samples containing mixed genetic material from multiple _______. But DNA metabarcoding can.
DNA begins to _______ once it’s exposed to the environment. In the ocean, for example, it may only persist for a few days. So in many contexts, eDNA is useful for telling us about the recent past. The _______ of DNA metabarcoding starts with an environmental sample like a core of soil, a vial of water, some feces, an insect trap, or even the blood from leeches’ stomachs. ___________ then sift out everything aside from DNA by blending the sample up and using enzymes that _____ down cellular proteins and release DNA, which they purify. The result is a “soup” of all the DNA in the sample. Scientists then apply the __________ chain reaction or PCR, which uses artificial DNA strands called universal primers. These primers bind to DNA sequences that are _______ across species, then _______ _______ barcodes that are species-specific. High-throughput sequencing then reads millions of these DNA fragments, simultaneously. And finally, researchers compare them to reference _________ and identify how many and which species are present— or if they’ve found entirely new ones. This method has led to the _________ of tens of thousands of species over the past decade.
Solution
- amplify
- discovery
- species
- environmental
- databases
- polymerase
- clouds
- constantly
- similar
- process
- shedding
- break
- degrade
- bottom
- researchers
- genetic
Original Text
The world is covered in DNA. It’s all around us— on the ground, at the bottom of the ocean, and up in the clouds. Multicellular organisms are constantly shedding cells. But until recently, eDNA wasn’t very useful to us. Traditional scientific techniques couldn’t parse environmental samples containing mixed genetic material from multiple species. But DNA metabarcoding can.
DNA begins to degrade once it’s exposed to the environment. In the ocean, for example, it may only persist for a few days. So in many contexts, eDNA is useful for telling us about the recent past. The process of DNA metabarcoding starts with an environmental sample like a core of soil, a vial of water, some feces, an insect trap, or even the blood from leeches’ stomachs. Researchers then sift out everything aside from DNA by blending the sample up and using enzymes that break down cellular proteins and release DNA, which they purify. The result is a “soup” of all the DNA in the sample. Scientists then apply the polymerase chain reaction or PCR, which uses artificial DNA strands called universal primers. These primers bind to DNA sequences that are similar across species, then amplify genetic barcodes that are species-specific. High-throughput sequencing then reads millions of these DNA fragments, simultaneously. And finally, researchers compare them to reference databases and identify how many and which species are present— or if they’ve found entirely new ones. This method has led to the discovery of tens of thousands of species over the past decade.
Frequently Occurring Word Combinations
ngrams of length 2
| collocation |
frequency |
| dna metabarcoding |
3 |
Important Words
- amplify
- apply
- artificial
- barcodes
- begins
- bind
- blending
- blood
- bottom
- break
- called
- cells
- cellular
- chain
- clouds
- compare
- constantly
- contexts
- core
- covered
- databases
- days
- decade
- degrade
- discovery
- dna
- edna
- environment
- environmental
- enzymes
- exposed
- feces
- finally
- fragments
- genetic
- ground
- identify
- insect
- led
- material
- metabarcoding
- method
- millions
- mixed
- multicellular
- multiple
- ocean
- organisms
- parse
- pcr
- persist
- polymerase
- primers
- process
- proteins
- purify
- reaction
- reads
- reference
- release
- researchers
- result
- sample
- samples
- scientific
- scientists
- sequences
- sequencing
- shedding
- sift
- similar
- simultaneously
- soil
- species
- starts
- stomachs
- strands
- techniques
- telling
- tens
- thousands
- traditional
- trap
- universal
- vial
- water
- world