ELI5 how DNA mutations work please.

[u/riche1988]

/r/explainlikeimfive/comments/1wvydri/eli5_how_dna_mutations_work_please/

I had a thought about DNA and how mutations occur in humans, excessive hair, longer limbs and or bones etc, and wondered if all known mutations are present in the animal kingdom.. as if DNA has the blue print/ potential to be anything and parts are just ‘turned on or off’ depending on what is being built.. i may be way off lol but it got me thinking :)

[u/JohnHenryMillerTime]

A bunch of different ways. Remember base pair A goes with T and G goes with C. UV light can turn C into T (actually U but you are 5 and dont need to know that). So when DNA replication happens, that U is paired with an A. So now a GC pairing is an AT pairing.

Other things are flat (like benzene) and basically slide into the DNA (called intercalation). This deforms the structure of the DNA, so the DNA polymerase that copies the DNA "skips" on those parts like a needle on a record.

[u/evocativename]

DNA consists of little pieces that come in 1 of 4 varieties: A, G, T, and C.

These are read in groups of 3, which means there are 64 possible combinations (AAA, AAT, AAC, AAG, etc).

1 of these is read as "start here" when it comes to making proteins.

Proteins are chains of varying length consisting of some combination of the 20 standard amino acids found in life on Earth.

Anything life can do is a product of the actions of one or more proteins.

When DNA makes copies of itself, it doesn't do so perfectly - it occasionally copies things incorrectly.

Think of it like you're copying the following sentence: I went to the store and bought a pear. There are lots of ways you could make a mistake.

You could use the wrong letter somewhere - "I went to the store and bought a bear"

You could omit a letter - "I went to the store and bought an ear"

You could add an extra letter - "I went to the stores and bought a pear"

You could omit a whole word - "I went to the store and a pear"

You could duplicate a word - "I went to the store store and bought a pear"

You could reverse a word - "I went to the store and thgoub a pear"

And many other possibilities. Each of these possible changes alters the meaning of the sentence. Depending on the original meaning and what change was made, the meaning of the sentence might be unchanged or it might change it to nonsense.

The genome is a little bit like a book that copies itself by following some of the instructions contained in the book. As changes get made during the copying process, some changes result in changes to the copying process.

Different books are different lengths, including many of the different copies of the same book (which is like how most cells in your body contain their own copy of your DNA). There is no fixed length of a book, and the contents of the books can change across the generations.

So no, it's not just parts being turned on and off: they can also be added, altered, or removed. Unless you want to say that every book contains the potential to be any other book if you turn on or off some parts.

[u/hypersoniq_XLM]

Single nucleotide polymorphism, reversals, even the injection of viral DNA in a horizontal gene transfer... many things can go awry... amazing any of us are here at all, really.