FellowConspirator t1_ivfiqoh wrote
Of 3.2 billion bases, about 10 million bases are known to be variant, and on average each person has 100 thousand or so of those variants.
We’re all genetically distinct and unique, but we’re overwhelmingly similar to one another. The reference genome provides a structure upon which we can make notations of variation, localization of features / functions, etc.
MozeeToby t1_ivfpuys wrote
In addition to this, the human genome serves as a reference genome. You don't need to say "this patient has this string of 500 base pairs representing their variant" you can just say "at position 125 they have a GTA instead of ATA and at 244 they have 6 duplicated pairs"
BeardOBlasty t1_ivhmayn wrote
Yea I've always understood genes as being the beginning framework, and then as you grow and develop the little differences along the way is what make the unique human.
I always thought identical twins are the example that very similar genes can still result in very different people....or not. It's all about how the framework grows in it's environment.
julie78787 t1_ivi1vcy wrote
Identical twins will not have the exact same DNA at every point in each of their chromosomes. Each a cell divides, including the division which resulted in twinning, some number of mutations are likely to occur.
SuitableClassic t1_ivj99ay wrote
Is that why my identical twin is an ugly dofus, and I'm gorgeous beyond compare?
slouchingtoepiphany t1_ivk2qlk wrote
That's correct, the genes for beauty disproportionately went to you, unfortunately, the genes for intelligence might have gone the other way. Only kidding!!! :)
[deleted] t1_ivppoud wrote
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Dyvion t1_ivjgy3v wrote
See the movie, "Twins" for a true to life perfectly real example of this.
heresacorrection t1_ivgtoop wrote
On average we expect an individual to have millions of variants that differ from the reference. Most of which are inconsequential (i.e. not malignant).
In addition, relative to the reference, the variability is dependent on your origin.
"Consistent with the out-of-Africa model of human origin, the number of variant sites per genome is highest among Africans (∼5 million variants) compared with individuals of East Asian, European, or South Asian ancestry (∼4.0–4.2 million variants) "
ivan_drago27 t1_ivh98dx wrote
Such a good note to add on the out-of-Africa model, thank you for including that. Been a few years since I actively studied this stuff and that made me want to dig into some theory again.
CaptainHunt t1_ivgay0v wrote
Also, while the sample size was comparatively limited, samples were taken from a wide variety of people from all over the world.
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