I don't know almost nothing of genetics but I felt a little interested in the subject of genetics and its role in intelligence and i found to reports that talk about certain genes that contribute to intelligence

https://www.nature.com/news/smart-genes-prove-elusive-1.15858 https://www.newsweek.com/how-be-smart-intelligence-linked-500-genes-large-new-study-842454

What I don't understand is if only some people have this 500 genes or all human population has this genes?


1 Answer 1


Is IQ heritable?

Let me start by saying that there is no commonly agreed upon method to measure IQ (thank you @mdperry). Keeping this in mind...

Yes, studies have shown that IQ is heritable. Or rather, IQ has a heritability that differs from both 0 and 1, meaning that both environment variation and genetic variation plays a role in determining an individual's IQ. Studies show IQ heritability varying between 0.5 (ref) and 0.8 (ref). For more information, please have a look at this post.

To understand the concept of heritability, please have a look at Why is a heritability coefficient not an index of how “genetic” something is?.

What are the genes that contribute to it?

IQ is a polygenic trait, meaning that many loci (locus = position in the genome) are affecting the variation in IQ. For more information about those loci, please have a look at this post.

What I don't understand is if only some people have this 500 genes or all human population has this genes?

Your misunderstanding comes from a misunderstanding about the concepts of gene and allele. You should start by having a look at the definition of the three following terms

Below, I will not comment about the 500 genes claimed in this popular article and will just consider them as valid without considering the complication behind the methodology used for such estimation and about what original articles this popular article is citing.

With the exception of eventual copy number variation, the entire human population share these 500 genes but not everyone has the same allele at these 500 loci.

  • $\begingroup$ You say that IQ is polygenic and many genes affect IQ, but theres evidence of certain genes that certain population has but other population dont have? im not talking about alleles $\endgroup$
    – Roby
    Commented Aug 5, 2018 at 2:27
  • $\begingroup$ I don't understand your comment. Are you making a claim or asking a question (there is a ? but the sentence is not phrased like a question)? Are you talking about CNV? Are you now talking about among population variance (which was not the subject of your question)? $\endgroup$
    – Remi.b
    Commented Aug 5, 2018 at 2:30
  • $\begingroup$ Oh nevermind im just very bad at formulating scientific questions hahaha, anyway thanks for the initial response and for clarify my doubts. $\endgroup$
    – Roby
    Commented Aug 5, 2018 at 2:34
  • $\begingroup$ @Roby If you consider that the answer has answered your question, then you can click the checkmark next to the answer so as to mark the post as answered. $\endgroup$
    – Remi.b
    Commented Aug 5, 2018 at 16:18
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    $\begingroup$ I would be remiss if I did not mention that there is no accepted method to determine the IQ of an individual. $\endgroup$
    – mdperry
    Commented Aug 6, 2018 at 14:11

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