3 ms·

"Replication tests show that these predictors capture, respectively, ~40, 20, and 9 percent of total variance for the three traits. ". This seems very low, alm

by petra 9y ago

"Replication tests show that these predictors capture, respectively, ~40, 20, and 9 percent of total variance for the three traits. ". This seems very low, almost like saying genes don't have any practical predictive power, right ?

deleted 9y ago
[deleted]
joe_the_user 9y ago
Well, it would be pretty astounding if genes (edit: genes by themselves) were a strong predictor of height. We've seen average height go up tremendously in places like Japan based on improved nutrition.
- bobcostas55 9y ago
  Genes are a strong predictor of height (in certain populations), AND it has gone up tremendously in places like Japan. Both are true. To speak of the influence of genes also assumes a certain environment. If we look at western populations for example, the heritability of height in adulthood is something like 0.8. But this is predicated on that western environment where ~nobody has nutritional deficiencies. A uniform, high-quality environment means that there is little besides genes that can influence height. If something happened and a large portion of the population had such deficiencies, the influence of genes would be diminished.
gwern 9y ago
What criterion are you using in which 40% of variance is zero practical predictive power?
jamesmishra 9y ago
In his book Behave[1], biologist Robert Sapolosky explains the issue as follows: > Heritability scores are relevant only to the environments in which the traits have been studied. The more environments you study a trait in, the lower the heritability is likely to be. He goes on for several pages, describing the ways the surrounding environment can change an organism's gene expression, and I think this quote best summarizes his point: > Here’s a rule of thumb for recognizing gene/environment interactions, translated into English: You are studying the behavioral effects of a gene in two environments. Someone asks, “What are the effects of the gene on some behavior?” You answer, “It depends on the environment.” Then they ask, “What are the effects of environment on this behavior?” And you answer, “It depends on the version of the gene.” “It depends” = a gene/environment interaction. [1]: https://www.amazon.com/Behave-Biology-Humans-Best-Worst/dp/1594205078 https://www.amazon.com/Behave-Biology-Humans-Best-Worst/dp/1...
- StavrosK 9y ago
  Not very related, but Sapolsky's A primate's memoir is a very funny and edifying read. Strongly recommended.
patall 9y ago
No, this only says that the about 20000 SNPs (mutations) that they can accurately measure have a limited effect on variance. What the millions of other SNPs do is not known. For example there are estimates for many many thousands of SNPs that influece your height by 0.1 mm. The single variant effect is tiny but altogether it adds up a lot. Oh, and lets not forget that again this is only point mutations (SNPs). But there are also genomic insertions, deletions, larger structural variants and poly variant interactions, all of which we do not really have much idea about or even the tech available to accurately measure.

by petra 9y ago

deleted 9y ago

[deleted]

joe_the_user 9y ago

Well, it would be pretty astounding if genes (edit: genes by themselves) were a strong predictor of height. We've seen average height go up tremendously in places like Japan based on improved nutrition.

bobcostas55 9y ago
Genes are a strong predictor of height (in certain populations), AND it has gone up tremendously in places like Japan. Both are true. To speak of the influence of genes also assumes a certain environment. If we look at western populations for example, the heritability of height in adulthood is something like 0.8. But this is predicated on that western environment where ~nobody has nutritional deficiencies. A uniform, high-quality environment means that there is little besides genes that can influence height. If something happened and a large portion of the population had such deficiencies, the influence of genes would be diminished.

gwern 9y ago

What criterion are you using in which 40% of variance is zero practical predictive power?

jamesmishra 9y ago

In his book Behave[1], biologist Robert Sapolosky explains the issue as follows: > Heritability scores are relevant only to the environments in which the traits have been studied. The more environments you study a trait in, the lower the heritability is likely to be. He goes on for several pages, describing the ways the surrounding environment can change an organism's gene expression, and I think this quote best summarizes his point: > Here’s a rule of thumb for recognizing gene/environment interactions, translated into English: You are studying the behavioral effects of a gene in two environments. Someone asks, “What are the effects of the gene on some behavior?” You answer, “It depends on the environment.” Then they ask, “What are the effects of environment on this behavior?” And you answer, “It depends on the version of the gene.” “It depends” = a gene/environment interaction. [1]: https://www.amazon.com/Behave-Biology-Humans-Best-Worst/dp/1594205078 https://www.amazon.com/Behave-Biology-Humans-Best-Worst/dp/1...

StavrosK 9y ago
Not very related, but Sapolsky's A primate's memoir is a very funny and edifying read. Strongly recommended.

patall 9y ago

No, this only says that the about 20000 SNPs (mutations) that they can accurately measure have a limited effect on variance. What the millions of other SNPs do is not known. For example there are estimates for many many thousands of SNPs that influece your height by 0.1 mm. The single variant effect is tiny but altogether it adds up a lot. Oh, and lets not forget that again this is only point mutations (SNPs). But there are also genomic insertions, deletions, larger structural variants and poly variant interactions, all of which we do not really have much idea about or even the tech available to accurately measure.