Name: how virus mutations drive outbreaks
Uploaded: 2019-03-11T09:21:24.000Z
Duration: 36 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-8

Viral Mutations

또한, 바이러스는 복제 시 구조상의 변화 때문에 유전적으로 진화할 수 있는데,이러한 진화를 돌연변이, 또는 유전 물질의 영구적인 변화라고 합니다.RNA가 존재하면 더 많은 오류가 발생하는데,그 이유는 복제를 하려면역전사효소가 필요하고, 역전사효소는 교정을 하지 않기 때문입니다.따라서 빠른 진화를 할 가능성과약물에 대한 저항을 가질 가능성이 높아집니다.이는 인체 면역 결핍 바이러스 또는 HIV에 해당하며,그렇기 때문에 싸우기가 힘든 것입니다.

Quan, Chuansong, Weifeng Shi, Yang Yang, Yongchun Yang, Xiaoqing Liu, Wen Xu, Hong Li, et al. "H7N9 인플루엔자 바이러스의 새로운 위협: 5차 유행에서 높은 게놈 다양성을 가진 고병원성 및 저병원성 변이의 확산 및 진화." Journal of Virology 92, no. 11 (2018년 6월 1일): e00301-18. [<a href="https://doi.org/10.1128/JVI.00301-18" target="__blank">소스</a>]

바이러스 돌연변이

돌연변이(mutation)는 유전체(genome)에서 일어나는 DNA나 RNA 서열의 변화입니다. 어떤 돌연변이는 유전체 복제 중 DNA나 RNA를 복제하는 중합효소(polymerase; 폴리머레이스)에 의해 만들어진 오류로 인해 발생합니다. DNA 중합효소와 달리, RNA 중합효소는 그 작업을 “교정(proofreading)”할 수 없기 때문에 오류가 발생하기 쉽습니다. 따라서 HIV와 같은 RNA 기반 유전체를 가진 바이러스는 DNA 기반 유전체를 가진 바이러스보다 더 빨리 돌연변이를 일으킵니다. 돌연변이와 재조합(recombination)이 적응 진화의 원천이 되기 때문에, RNA 기반 바이러스는 항바이러스제에 대한 저항력을 빠르게 진화시킬 수 있습니다.
 
 <h4>돌연변이를 비교하면 진화를 재구성할 수 있습니다</h4>
 
 현대 생물학의 주요 목표는 유전체 서열을 비교해 진화 역사를 밝히는 것입니다. 이러한 분석의 실용적인 예는 질병을 유발하는 바이러스의 진화에 대한 연구입니다. 유전체 서열분석(genome sequencing)은 굉장히 빠르고 저렴해져서 질병 발생 시 바이러스의 기원과 진행 중인 진화를 조사하는 것이 가능해졌습니다.
 
 예를 들어 2013년 중국에서 H7N9라고 불리는 신종 조류 인플루엔자가 출현하면서 인간에게 심각한 호흡기 질환을 유발했습니다. 인간과 몇몇 조류로부터 분리된 바이러스의 돌연변이를 비교해서 이 인플루엔자 균주(strain)의 조상이 아마도 닭에게 전염되기 전에 중국 내 오리 개체군에서 유래되었으리란 것을 밝힐 수 있었습니다. 조상의 균주는 이후 다른 조류 바이러스와 재조합되어 인간을 감염시킨 H7N9 균주를 생성했습니다. 이 분석은 살아있는 가금류를 파는 시장을 인간 감염의 가능성 있는 원천으로 확인하였습니다. 또한 H7N9 균주의 진화를 조사하는 동안 인간을 감염시킬 가능성이 있는 조류 인플루엔자의 추가 균주를 발견했습니다. 이 연구는 돌연변이의 진화적 분석이 전염병 발생 시 역학자들에게 어떻게 중요한 정보를 제공할 수 있는지를 보여줍니다.

돌연변이는 게놈에서 DNA 또는 RNA의 염기 배열이 변경되는 것입니다. 일부 돌연변이는 게놈의 복제 중에 발생합니다.

Education

교육

JoVE Core

Biology

생물학

Genetics

유전학

Viruses

바이러스

KEY TERMS AND CONCEPTS

주요 용어 및 개념

how virus mutations drive outbreaks

Virus mutations can change how quickly a virus evolves and spreads. A mutation is a change in the sequence of bases in DNA or RNA. Some mutations happen when the genome is copied. They are caused by errors made by polymerase enzymes, which replicate DNA or RNA.

RNA viruses often change faster than DNA viruses because RNA polymerase does not proofread its work. That means RNA-based genomes, such as HIV, can gather mutations more quickly. Mutation and recombination give viruses the raw material for adaptive evolution. As a result, RNA-based viruses can sometimes evolve resistance to antiviral drugs.

Scientists also use mutations to trace how viruses evolve over time. By comparing genome sequences, researchers can reconstruct evolutionary history. This is especially useful during disease outbreaks because genome sequencing is now fast and inexpensive. It helps scientists study where a virus came from and how it is changing.

The 2013 H7N9 avian influenza outbreak in China is one example. By comparing viruses from humans and several bird species, researchers found that the ancestor likely came from domestic ducks in China before spreading to chickens. That ancestral virus later recombined with other bird viruses to form the H7N9 strain that infected humans. The analysis also pointed to live poultry markets as the likely source of human infections and revealed another avian flu strain that may also infect humans.

How Virus Mutations Drive Outbreaks

what are viruses?

How Viruses Infect Cells and Multiply

Viruses infect cells and make new copies by using a host cell’s own machinery. A virus is a tiny infectious particle with an RNA or DNA genome inside a protective protein coat. It cannot reproduce on its own, so it must enter a cell to make more viruses. After infection, the virus sheds its protein coat and uses the host cell to transcribe and translate its genetic material. The cell then assembles many new viral particles. In many cases, these new viruses rupture the host cell and kill it.

viral structure

How Virus Shapes Help Infection

Viruses have specific structures that help them infect host cells and trigger immune responses. Each virus has a core that contains either a DNA-based or RNA-based genome. That core is surrounded by a protective protein coat called the capsid. The capsid is made of smaller subunits called capsomeres. The capsid and the genome-containing core together are called the nucleocapsid. Viruses are often grouped by capsid design. Most viruses have either icosahedral or helical capsids, but some have...

lytic cycle of bacteriophages

How Phages Infect and Burst Bacteria

Bacteriophages, or phages, are viruses that infect bacteria. They have a distinctive head-tail shape. In the lytic cycle, a phage first attaches to the outside of a bacterial cell. Tail proteins bind to specific receptor proteins on the bacterium’s surface. After attachment, the phage tail injects its DNA genome into the bacterial cytoplasm. The phage then uses the bacterium’s cellular machinery to make proteins needed for replication and dispersal. When phage replication is complete, some of...

lysogenic cycle of bacteriophages

Prophage Integration in Bacteria

The lysogenic cycle shows how bacteriophages can infect bacteria without killing the host right away. In this cycle, the phage genome joins the bacterial genome. The integrated phage DNA is called a prophage, and the bacterium copies it each time it replicates. Some prophages can switch back into the lytic cycle. This change can happen after DNA damage or even without an obvious outside trigger. When the prophage is induced, the phage begins making new virus particles again. Prophages can...

retrovirus life cycles

How Retroviruses Replicate in Host Cells

Retroviruses replicate by copying their RNA genome into DNA inside a host cell. After entry, the viral enzyme reverse transcriptase makes a double-stranded DNA copy from the single-stranded RNA genome. The viral DNA is then carried into the nucleus and inserted into the host genome by integrase. Once integrated, the retroviral DNA is transcribed whenever the host genome is transcribed. This produces new viral RNA that can be copied and used again. The new RNA moves into the cytoplasm, where it...

viral recombination

How Viruses Swap Genes and Spread

Viral gene swapping can happen when more than one virus infects the same cell. After the viruses break open and expose their genomes for replication, matching regions can pair up and exchange sequences. This process is called recombination. Viruses with segmented genomes can also swap whole segments, which is called reassortment. These changes can help create new diseases. Some diseases can infect more than one species. Pigs can be infected by some human and bird viruses, along with the...

viral mutations

Virus mutations can change how quickly a virus evolves and spreads. A mutation is a change in the sequence of bases in DNA or RNA. Some mutations happen when the genome is copied. They are caused by errors made by polymerase enzymes, which replicate DNA or RNA. RNA viruses often change faster than DNA viruses because RNA polymerase does not proofread its work. That means RNA-based genomes, such as HIV, can gather mutations more quickly. Mutation and recombination give viruses the raw material...

key terms and concepts

Learn how RNA and DNA virus mutations differ, why RNA viruses evolve fast, and how genome sequencing helps track outbreaks like H7N9 influenza.

How Virus Mutations Drive Outbreaks | JoVE K12

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Next Generation Science Standards

Life Science

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-2

Texas Essential Knowledge and Skills

BIO.5

BIO.5.D

Georgia Standards of Excellence

9-12

Entomology

SEN4.

SEN4.a

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HS-LS1-1

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HS-LS1-2

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HS-LS1-3

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HS-LS1-4

How Virus Mutations Drive Outbreaks

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