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It doesn't. Viruses don't "know" anything. Mutations occur at random. Most of them don't do anything, or have a slight negative effect on the ability of the virus to infect and reproduce. However, there are billions and billions of viruses. Once in a while a random mutation will offer a significant advantage like immunity to an anti-viral drug. The viruses ...
12
This is molecular evolution and is completely undirected.
Mutations happen all the time, most of them disappear without anyone noticing, since they have no evolutionary advantage to permeate.
This is different when you treat the cells and put them under an evolutionary pressure. Under this conditions, mutations which affect the mechanism of the drug (as ...
7
Summary: They Don't.
Long explanation:
Mutations happen at random. A series of factors can lead to the perceived notion that the mutation was intentional.
The mutation can be harmful, beneficial, or neutral.
Harmful: We don't see the harmful mutations as these individuals don't proliferate. The mutant individual just dies off without passing their ...
3
Spotted hyenas are a matriarchal society and female hyenas are larger than males. Also, female hyenas dominate males.
3
In certain species of parasitic wasp, contained within the wasp genome is the genome for a so-called "polydnavirus". The female wasp somehow creates instances of these polydnaviruses inside its ovaries.
When the wasp injects an egg into a member of the host species (likely a caterpillar), several instances of the polydnavirus are also injected along with it....
3
In the context of Darwin's Variation under Domestication, "true breeding" is a phenotypic characteristic rather than a genetic one. True-breeding organisms produce offspring that are identical to themselves, concerning some trait -- i.e. white fantails, when bred with white fantails, produce characteristically white offspring. For diploid organisms, true-...
2
Yes, but it's relatively rare.
The disease progresses more rapidly in homozygotes than in heterozygotes.1
Reference
1: Ferdinando Squitieri, Cinzia Gellera, Milena Cannella, Caterina Mariotti, Giuliana Cislaghi, David C. Rubinsztein, Elisabeth W. Almqvist, David Turner, Anne‐Catherine Bachoud‐Lévi, Sheila A. Simpson, Martin Delatycki, Vittorio Maglione, ...
2
Jackson Labs offers a service for this for what looks like a reasonable price. I have no experience with the service other than general good feelings about Jackson.
We have a unique selection of mouse single nucleotide polymorphism (SNPs) panels useful for a diverse set of mouse research applications.
Applications of SNP scanning services
...
1
I'm not sure what you mean by "complex", but many diseases are known to arise due to exposure due to toxins in the environment.
A good example of this is exposures to some metals including arsenic, lead, and mercury. See for example this information from the US NIH and the wikipedia article on metal toxicity.
In the case of arsenic, some of this ...
1
Case A: Not Breeding True
If you cross-breed two random dogs, the offspring are likely to only vaguely resemble either parent. If you could clone a random dog to obtain two genetically identical dogs with different sex, you would likely still only get offspring that vaguely resemble their parents, because the chromosomes of the parents would come in pairs ...
1
I can't find a reference to a "TARIS model" in the paper you linked, but we can break down the molecular circuitry of this lineage tag tracking system step-by-step.
The authors use a type of Tet expression system in order to tightly control the expression of a hyperactive Sleeping Beauty (HSB) transposase. In the absence of doxycycline, the reverse ...
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