43 votes
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How many times has SARS-CoV-2 mutated?

This question makes a number of incorrect assumptions and I don't have time to correct them. The short answer is that the virus has mutated probably hundreds of times since it entered humans in late ...
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37 votes
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Are mutations a source of genetic variation?

Going through the possible answers (A) Rates tend to be very high in most populations. This is a very unclear statement. What does "high" mean? In humans, the average mutation rate per ...
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22 votes
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Can the SARS‑CoV‑2 virus mutate in people who have been fully vaccinated?

Since vaccination is not 100% protective against infection (i.e. the virus can sometimes succeed in establishing and replicating in a vaccinated host's body), the answer is yes. Furthermore, since ...
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18 votes

Is Mutation Theory still "valid" for complex organisms?

Change in genetic variance From what I have been taught, Natural Selection (or even Artificial Selection) is great for panning favorable genes from a species and bringing them to the fore, however, ...
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18 votes
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How do we explain the white feathers of an albino peacock?

The surface structuresa that are responsible for the structural coloration of peacock feathers are actually barbules and rods made of the very same biopolymer that is responsible for pigmentation in ...
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  • 2,048
14 votes

What has caused life to choose this unfathomably tiny subset of all possible proteins?

The answer is chance or, even better, contingency. About your calculations, it is true that the theoretical sequences are almost unlimited, but the basic scaffolds are not. Very different sequences ...
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13 votes
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Are all mutagens carcinogens?

Short answer All mutagens are potential carcinogens unless the mutagen is highly specific to a site. As noted in the question, carcinogens need not be mutagenic. HPV causes oncogenic transformation ...
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13 votes
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How does Darwinian Evolution work?

I accidentally wrote a lot! I first discuss the term Darwinian evolution. I then describe the main evolutionary processes insisting on the two elements of interest in your question, that is mutations ...
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13 votes

Are all carcinogens mutagens?

How can a non-mutagenic agent be carcinogenic? An agent that causes overexpression of oncogenes or inhibition of tumor suppressors, would be carcinogenic but not mutagenic. HPV, for instance, produces ...
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13 votes
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Do mutations occur while growing virus for preparing inactivated viral vaccine?

Very simply, mutations do occur, as they do for any cultured organism. This is a well recognized problem in many fields of biology where organisms are cultured and remains in particular a problem for ...
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12 votes

Is Mutation Theory still "valid" for complex organisms?

You're right that the mutation must be in a germ cell in order to be passed on. Most errors are introduced during DNA replication (at a rate of around 10-10), which occurs a number of times between ...
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12 votes

Why are cancer rates low in large animals?

Short answer Large animals do get cancer. They may contract cancer with an incidence less than that estimated by absolute cell numbers, but there seems to be a lack of data on cancer rates in large ...
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12 votes

Are all carcinogens mutagens?

Alcohol itself is non-mutagenic because it does not directly alter DNA. (Additionally ethanol enhances carcinogenesis and is itself not a carcinogen - updated) There are similar non-mutagenic ...
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11 votes

Has a beneficial mutation ever been documented?

The answer depends on what you mean by "observed". Bacteria acquire antibiotic resistance genes all the time, for example. This happens 'in the wild', but you can see in the lab that bacteria can ...
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10 votes
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What is the difference between Single Nucleotide Polymorphism (SNP), Mutation and Structural Variation(SV)?

Lets state what a Mutation is first. Mutation: A mutation is any change in an organism's genetic sequence which varies from that of the wild-type reference sequence (hg19/GrCH37 from 2009 or hg38/...
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Saturated Mutagenesis Screening

This sort of method is indeed quite useful and frequently used in synthetic biology: I've used a similar approach before to generate 5' insulators for promoters. Calculating the exact theoretical ...
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9 votes

Why isn't the insertion of a single nucleotide destructive for DNA?

A single substitution can often be silent, or at least not impact the structure and function of the resulting protein in a significant way. But what you describe is a frameshift, and that is one of ...
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What are the major causes of mutations in DNA?

Welcome to Biology.SE! can environmental factors play a role in the amount of mutations that occur? Yes! The environmental factors that increase the mutation rate are called mutagens. You will ...
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9 votes
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How close genetically is the most human-like chimpanzee to the most chimp-like human?

You may be interested in this 2005 Nature paper from the Chimpanzee Sequencing and Analysis Consortium: Initial sequence of the chimpanzee genome and comparison with the human genome. It breaks down ...
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Are mutations random?

Short answer The claim is unclear but is essentially misleading and wrong. However, IMO, for lay people, it is a good approximation to just think that mutations are random! Here, on Understanding ...
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8 votes
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What if a Point Mutation is seen in only half the coverage for its location?

I don't know, whether the organism you are working with is diploid, but suspect it's an animal (or even a mammal), so the most parsimonious explanation would be that you have homozygotes and ...
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8 votes
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Isn't biological immortality strictly speaking impossible?

Good question. There are many organisms that are technically biologically immortal. However, I would like to point out that the definition of biological immortality is this: ...cells that are not ...
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  • 1,846
8 votes
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Are four-leaf clovers mutations, developmental errors, or something more complicated?

A recessive gene for four leaves has been identified (Tashiro et al., 2010). The clover is a tetraploid species and together with the fact that environmental conditions may also suppress the ...
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8 votes

Is it plausible that strict lockdowns made it more likely for the new variant of COVID to have emerged?

While I get your intuition, the hypothesis seems implausible Emerge of new CoV variants should be considered proportional to the current spread of the virus. Each virus has a certain mutation rate ...
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8 votes

Amino Acid mutation profile for human coronavirus: Why is the mutation from T to I so frequent?

The change from C to T (or U in the case of RNA) can happen via the oxidation and deamination of the Cytosine (see reference 1 for the explanation of the mechanism). The mechanisms looks like the ...
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7 votes
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(How) can a pink grasshopper exist?

Pink individuals of the katydid species Amblycorypha oblongifolia are a relatively uncommon but natural phenomenon with a long history of research. It looks from popular press accounts (Science ...
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7 votes
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Most human-like teratoma ever recorded?

There's a 2003 paper published in the Journal of Korean Medical Science describing a case of a 'homunculus' within a teratoma: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055135/ It contained some ...
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7 votes

Is it possible to express a mutant gene only in a specific tissue?

It is called conditional mutation. You flox (put lox sites around) gene of interest and express Cre recombinase driven by tissue-of-interest-specific promoter. Illustration from here: Using ...
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7 votes

Do mutant alleles result from mutation of the wild type?

No, not necessarily! The terms might be confusing I agree. The most common allele (the wild type allele) might be a mutant of one other type of allele (one mutant allele) present in the population. ...
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Why is mutation rate high in introns?

Not less efficient, but introns are under less selective pressure than exons. Exons actually encode the protein. A single bp insertion will ruin a mRNA encoding a protein by causing a frame shift in ...
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