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sunplaysbass t1_isgminf wrote

Reply to comment by adc34 in When it's said 99.9% of human DNA is the same in all humans, is this referring to only coding DNA or both coding and non-coding DNA combined? by PeanutSalsa

Half a percent range seems huge to me. But that’s my no nothing reaction.

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Ixosis t1_isgv0ig wrote

Really isn’t that large when you find out we share 70% of our DNA with bananas

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sunplaysbass t1_isgvgdx wrote

To me that is why 0.6% variance within humans is a lot, if we’re 30% off from being a banana.

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powercow t1_ish1kn3 wrote

from what i read, we have less variation than other animals. due to some event 70,000 years ago that caused our population to collapse to only a few thousand

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PhilosopherFLX t1_ishdx0a wrote

Always wonder how that squares with Neanderthal interbreeding when Neanderthals mostly lived 130,000 to 40,000 years ago, right in the middle of 70,000.

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ECEXCURSION t1_ishvhah wrote

Maybe Neanderthals hunted humans to the brink of extinction. Just like humans and vampires!

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Sylvurphlame t1_isirxzk wrote

Nah. A giant race war is something humanity would never engage in…

Wait…

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Angdrambor t1_isjtgb1 wrote

Makes you wonder if they hit that same bottleneck before we wiped them out.

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Xais56 t1_ishh9ox wrote

Depends on the animal. I doubt cheetahs have much variance.

Something hardy and successful and desired by humans though I could see having huge variance. Cannabis plants must have incredible variance between sexually produced individuals. (I'm aware it's not an animal, but the point stands).

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powercow t1_ishztdj wrote

oh for sure some have similar or even less than us. I was talking more about on the average side of things, we are a bit less genetically diverse than most. But especially among endangered species id expect diversity to be likely to be lower than ours. Not all that long ago they discovered a family of stick insect that everyone thought was extinct, living in a bush on a remote island. Since only a single family of them were found, its unlikely they are as diverse as we are.

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LoreChano t1_ishdssl wrote

So this was about the time we started to create art and religion, among other things? I wonder if it's related.

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jadierhetseni t1_isgwy84 wrote

Eh. It’s hard to overstate how much of the genome isn’t code-specific. That is, some of it is useless, some of it is structural (need x bases of any sort), some of it is compositional (need a lot of g and c but the precise ratio isn’t important) etc

A lot of the major protein-coding, structural, and regulatory stuff is highly conserved, so there’s a lot of overlap between any two species (Eg humans + bananas)

But all of that other stuff? Eh. It can vary basically as much as it wants consequence-free, producing a lot of within species differences.

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BiPoLaRadiation t1_isgxrl6 wrote

To be fair the percentage of genes that are different is probably a lot higher than 30 percent. The 30 percent is the number of base pair sequences that are similar between humans and bananas. So us and bananas both have a gene for a sodium pump or some other gene that is shared between most living things and on average the similarity between our average gene and their average gene (of the roughly 7000 genes that they compared in the original study) is about 40 (actual original number) percent (or less because they tested gene products and not base pairs so a lot of minor variability will still result in the same protein product).

If you were to compare on a gene by gene basis then probably none of our genes would be the exact same as a bananas. We and bananas also have multitudes of genes that are exclusive to us or them due to the structural differences and the long long evolutionary divergence.

So a 0.6% difference in genetic sequence between humans including not just base pairs of genes but also non coding sequences is actually really tiny. It's enough of a difference to do a lot but it's not as big of a difference as you are imagining.

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Sylvurphlame t1_isis7ih wrote

The way my biology professor explained it, assuming I recall correctly after decades, is that it takes most of the DNA just to make a functional life from of any sort of complexity. So the amount the separates species, or individuals within a species is relatively small. But important.

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bschug t1_isj3h9q wrote

Is that overlap the same for every human, or are some humans closer to a banana than others?

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sunplaysbass t1_isjecm7 wrote

Given this variance I can only assume some humans are closer or farther from being a banana than others. It could be a new path for eugenics, or perhaps a banana cult ranking system.

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danby t1_islfy04 wrote

> To me that is why 0.6% variance within humans is a lot

Sure but this includes non coding and repetitive DNA which between individuals is somewhat unconstrained. If you look at only protein coding genes you get back down to variances closer to 0.1%

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dunnp t1_ishmgl8 wrote

That’s comparing just coding regions with bananas, not the non-coding regions which are the vast majority of the human genome. So more like 70% of the coding 2% of the genome are shared with bananas.

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Thormeaxozarliplon t1_ishpbj8 wrote

That's only anecdotal. It's meant to show the common evolution of life. Most of that similarity is due to things like "housekeeping" genes and common biochemistry.

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TomaszA3 t1_ish7nri wrote

I'll just drop here that small things can disable or enable almost entirety of other "code". Like, change an "if" to opposite symbol, 0.0...1% of the code has been changed but 99.9...% of code is not executing at all. Or only half of total code is executing on one branch and other half at another.

0.6% in such very highly flexible codebase should definitely bear massive functional(or not, but evolution) changes.

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sometimesgoodadvice t1_isp75d7 wrote

An interesting analogy but slightly flawed in terms of looking at genomes of already viable organisms. A person whose genome is sequenced to compare to the reference has already undergone the selection criteria for viability and development. Basically, there are plenty of sites where single mutations would lead to a complete breakdown of making a "human" but those would never be seen in a sequenced genome.

The other main difference is that of course code is written to be concise and concrete. As far as I know, no one pastes in some random code that doesn't perform a function just in case it may be needed in the future. Of course, biology works precisely in that way and the genome is a mess of evolutionary history with plenty of space for modification without really resulting in any functional change. So a better example of those 0.6% may be that you can have typos in the comments of the code. In fact, for any large piece of software, I would be surprised if the comment section did not contain at least 0.5% typos.

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