biology

RaTG13

RaTG13 is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand RaTG13 rather than just read about it. In short: Bat coronavirus RaTG13 is a SARS-like betacoronavirus identified in the droppings of the horseshoe bat Rhinolophus affinis. It was discovered in 2013 in bat droppings from a mining cave near the town of Tongguan in Mojiang county in Yunnan, China.

Key takeaways

RaTG13 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RaTG13 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RaTG13 from memory before moving on to harder problems.

Reference excerpt

Bat coronavirus RaTG13 is a SARS-like betacoronavirus identified in the droppings of the horseshoe bat Rhinolophus affinis. It was discovered in 2013 in bat droppings from a mining cave near the town of Tongguan in Mojiang county in Yunnan, China. In February 2020, it was identified as the closest known relative of SARS-CoV-2, the virus that causes COVID-19, sharing 96.1% nucleotide identity. However, in 2022, scientists found three closer matches in bats found 530 km south, in Feuang, Laos, designated as BANAL-52 (96.8% identity), BANAL-103 and BANAL-236.

History In the spring of 2012, three miners cleaning bat feces in an abandoned copper mine near the town of Tongguan in Mojiang Hani Autonomous County developed fatal pneumonia. Out of concerns that the miner's cases could represent a novel disease, serum samples collected from the miners were sent to the Wuhan Institute of Virology and tested by Shi Zhengli and her group for Ebola virus, Nipah virus, and bat SARSr-CoV Rp3. The samples tested negative. To uncover a possible cause of the infection, different animals (including bats, rats, and musk shrews) were also sampled in and around the mining cave. Between 2012 and 2015, Shi Zhengli and her group isolated 293 different coronaviruses (284 alpha- and 9 beta-coronaviruses) from bat feces samples in the cave. One of the samples collected in 2013 from Rhinolophus affinis (the intermediate horseshoe bat) contained a novel sequence of ribonucleic acids later identified as "RaTG13". In 2020, Shi and her group retested the serum samples from the miners for SARS-CoV-2. The samples tested negative. In 2020, the strain identified in the sample was renamed from the original Ra4991 (4991st sample collected from Rhinolophus affinis) to "RaTG13", to reflect the originating bat species (Ra from Rhinolophus affinis), geographic location (TG from Tongguan), and year collected (13 from 2013). The name change has been considered innuendo by advocates of the lab leak theory for the COVID-19 pandemic.

Virology

The sequence of RaTG13 was reconstructed from metagenomic sampling (a common practice in environmental virology), and as such, could potentially be an in-silico chimera. RaTG13 has not been confirmed to exist in nature, to have been cultured or isolated in any laboratory, or to be a viable human pathogen. A live virus "RaTG13" has never been detected in any laboratory sample from the WIV or elsewhere. Based on its sequence, RaTG13 is a positive-strand RNA virus with an outer membrane. Its genome is approximately 29,800 nucleotides. The genome encodes a replicase (ORF1a/1b) and four structural proteins; including a spike protein (S), membrane protein (M), envelope protein (E) and nucleocapsid protein (N); and five viral accessory proteins, including ORF3a (NS3), ORF6 (NS6), ORF7a (NS7a), ORF7b (NS7b) and ORF8 (NS8). RaTG13 bears strong resemblance to the SARS-CoV-2 genome (it shares 96.1% nucleotide similarity), and its identification in animal droppings is a supporting piece of evidence for SARS-CoV-2's natural origin. The main area of divergence between RaTG13 and SARS-CoV-2 is in the receptor-binding domain (RBD) of the spike protein (S), which is the portion that binds to the receptor protein on the surface of the host cell and causes infection. The divergence in this domain indicates that, unlike SARS-CoV-2, the RaTG13 virus might not use angiotensin-converting enzyme 2 (ACE2) as its entry site into the cell. Further, the S protein of RaTG13 virus lacks the furin cleavage motif RRAR↓S. The binding affinity between RATG13 and hACE2 is lower than that between SARS-CoV-2 RBD and hACE2.

Phylogenetics

Phylogenetic tree A phylogenetic tree based on whole-genome sequences of SARS-CoV-2 and related coronaviruses is:

See also Bat SARS-like coronavirus RsSHC014 Bat SARS-like coronavirus WIV1 Mòjiāng virus

References

Worked examples

Example 1 — a first encounter with RaTG13

Start with the simplest possible case. Write down what RaTG13 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to RaTG13 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about RaTG13 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of RaTG13

In research: RaTG13 appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses RaTG13 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: RaTG13 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal virology, Bat virome, Coronaviridae, so understanding it makes those chapters shorter.
In everyday life: Look for RaTG13 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study RaTG13 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RaTG13 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain RaTG13 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RaTG13 in simple terms?

Why does RaTG13 matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study RaTG13?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on RaTG13.