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Galaxy-Hitchhiker42 t1_izozi63 wrote

Reply to comment by supamee in How did viral DNA become part of the human genome? by emelrad12

> mistakes can and do happen in the copying process

What are some causes for these mistakes ? Is it a crucial 'ingredient' the host body cannot provide at that moment ?

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Katamirand t1_izp0k2n wrote

Mutations are just natural mistakes that happen when replicating DNA. There’s so many bases to read that a mistake every now and then is inevitable. It happens a lot more than you’d think, but you only notice when a section of DNA that is important gets screwed up. There are huge stretches of DNA that don’t code for anything in humans, including the viral DNA that was introduced long ago.

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outlogger t1_izp4t7d wrote

The function of the DNA you referred to, that used to be called ‘junk DNA’, is still subject to research. It might not code for known proteins our bodies make under conditions that are so far researched but to say it doesn’t code for anything, I would say is wrong since we don’t know. Also, humans have inherited viral DNA that is a functional part of our genome, often functioning only if triggered by certain factors.

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ZacQuicksilver t1_izpapcf wrote

Here's a 200-page book, copy it by hand.

You may make a mistake.

That's DNA.

A virus's DNA is about 300 000 base pairs - which is about equivalent to a 200-page book. Granted, DNA has 4 characters while a book is written in closer to 64 - so maybe it's only a 65 page book; but you still have to copy it. Mistakes are going to happen.

Life generally takes two solutions to this: make a lot of copies as fast as you can and hope most of the books are still good; or take your time to make sure there are as few mistakes as possible.

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FogeltheVogel t1_izp3g5s wrote

Copying DNA is not a perfect process. Mutations naturally occur every now and then.

There's no particular cause, mutations are just a fact of life.

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ScaryLettuce5048 t1_izp5ekr wrote

I think u/Katamirand was referring to the "mistakes" in DNA replication during cell division. You should know that there are double-stranded DNA viruses that can infect and survive in the nucleus of the host cells while there are other viruses that have single-stranded RNA. In short, the polymerase in most RNA viruses cannot repair replication errors so these errors would be causes for mutations. So it's not so much of 'what the host cannot provide' that causes replication errors/mutations, but just think of it as a natural occurrence that not only can be caused by a multitude of factors, but also simply just by chance.

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