How and why do genetic mutations happen?
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Every cell in ones body is a variated copy of initial cell. They are copied and variated following instruction in dna. Thus if iniatial cell had damaged dna, this will be replicated through hole body. Same true if dna in cells were damaged after birth. All of that cell decendantce will carry damage unless that cell die faster. Later that body will produce eggs or semen, which will transfer dna damage to new born body (with 50% chance). Ut will be repeated unless some baby will be super lucky or new generation will die before it mate.
If such damage will be so grate that it will cause severe body missfunction then with 50% chance its offspring will have same desease.
So when copying genetic code, say in order to reproduce, you have a template that the cellular machinery can read and each of the 4 nucleotides that can be on a strand of DNA have a corresponding buddy they wanna hold hands with on the new strand that is being built. Adenine likes when it gets to hold hands with Tyrosine, but sometimes his cousin Uracil fill in. Tyrosine feels the same about Adenine. Guanine wants to be partnered with Cytosine and vice versa.
Now when you have 4 “letters” how do you use them to make all the intricate things inside the cell correctly, might I add?
Although each base pair is taken care of rung per rung, this is true for *replication*. And even though the dna strand is read and the correct companion inserted for it on the new strand, this is not a slow and accurate (in that it’s pretty darn close) process. Helicase is an enzyme that takes a 🧬 DNA double helix and and “unzips” it at an astronomical rate. At the same time, DNA Polymerase is in charge of creating the new strand. It binds to each nucleotide in a way that this brief configuration causes the correct matching nucleotide to be able to much more easily figure out where to go. These are floating around in the cytoplasm but they need a little help from the polymerase being like “ok this one needs guanine….get in here so I can glue you to the others”.
The polymerase does thousands of these matchups per second, and just about has one of the best rates of fidelity, a measure of how accurate the daughter strand is. But, there is no perfection because sometimes having a small degree of error is a good thing. Evolution really boils down to:
1. Cells (that organism are made of) need to make a copy of their genes so that they can multiply. Daughter cells need to work and all the instructions are there in the parent cell.
2. Copying the DNA is not perfect and errors happen, just like any machinery can have errors.
3. As long as the mutation does not prevent successful reproduction, it may not be a problem unless someone forgot. Conversely if it appears to result in more offspring they ever had.
4. as this causes differences in each successive generation and with enough time, speciation
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