Bold mine https://en.wikipedia.org/wiki/Molecular_evolution#MutationMutations are permanent, transmissible changes to the genetic material (DNA or RNA) of a cell or virus. Mutations result from errors in DNA replication during cell division and by exposure to radiation, chemicals, and other environmental stressors, or viruses and transposable elements. Most mutations that occur are single nucleotide polymorphisms which modify single bases of the DNA sequence, resulting in point mutations. Other types of mutations modify larger segments of DNA and can cause duplications, insertions, deletions, inversions, and translocations.
I was thinking about how (male) warlike aggression will never go away (I don't know what Junk DNA would mean). Bodily produced neurotransmitters and drugs (ethanol) and the overall survival of the species.
No one took this guy literally and it was just funny when I got to thinking about aggression -it was the thought that counted in my mind: https://www.reddit.com/r/AskMen/comments/9ht3nz/how_many_6yearolds_do_you_think_you_could_fight/ We can imagine threats that aren't there. Hostile aliens, AI or some genetically engineered super monster. We may have sublimated aggression for the progression of civilization. However, our imagination in lieu of the environment affects us.
It's easy to think that the survival of a species is primarily about procreation, however, a quantifiable argument can be made for this
https://www.upi.com/Science_News/20...s-early-evolutionary-advantage/3401518036102/ A man can produce more sperm in one ejaculation than a woman can produce babies in one life time. Also, sex and dopamine seemed a bit counterintuitive. Sure, you could make some lame porno plot of sex being exercise and you have to keep active to stay healthy, but a resistance to the neurotransmitter/drug my develop. (If not done on schedule?)The most successful primates today are characterized by irregularly elevated female survival.
As for ethanol, truth be told I'm dumber than a monkey. The only thing I remember of Darwrin was about a monkey observed getting wasted, but the hangover endured made him never touch it again. (750 mL 17% ABV Sherry mixed with 2 473 mL 5.5% ABV Beers and someone had to carry me home, put me in bed and I have no recollection of it.) Ethanol is a chemical not naturally produced by the body but its consumption I could surmise has affected DNA structure amongst different ethnic groups: https://en.wikipedia.org/wiki/Alcohol_tolerance#Alcohol_tolerance_in_different_ethnic_groups
Imagination, aggression, sex, survival and drugs are all meaningless without a brain. And I'd broadly say aggression, sex and survival are primally linked: Man have sex with woman. Woman get pregnant. Big man aggressively protect woman as sex object and would-be mother of child. Both, however, would sacrifice own life for child. Species lives on. Any and all political opinions all aside, the brain is electrochemical. Is say sex an instinct or a learned behavior? Ionizing radiation causes mutations but sex would be constantly reinforced with firing neurons i.e. electrons -it will never go away. Does this contribute to the structure of DNA in having such behavior constantly reinforced? (I also chose "sex" cause a three letter word.)