DNA Only Explains 5% (or 13%) of Inherited Traits – The Missing Heritability Problem

I like reading Rupert Sheldrake essays.  He does such a direct exposé of the weaknesses of science.  Oh, I am not a science basher.  That is not the reason I like him.  I wish the very best for science.  And I know he does, too.  At the same time I know that in many ways science is on the wrong track, and I am glad that, in Sheldrake, I have such a fellow frank-speaking well-wisher.

The latest new thing for me that Sheldrake points out is something called the “missing heritability problem.”  Ever heard of it?  Not me.

Wiki has only a VERY short article, which I can post in full here:

The “missing heritability” problem[1][2][3][4][5] can be defined as the fact that individual genes cannot account for much of the heritability of diseases, behaviors, and other phenotypes. This is a problem that has significant implications for medicine, since a person’s susceptibility to disease may depend more on “the combined effect of all the genes in the background than on the disease genes in the foreground”.

A model has been introduced that takes into account epigenetic inheritance on the risk and recurrence risk of a complex disease.[4]

The limiting pathway (LP) model has been introduced in which a trait depends on the value of k inputs that can have rate limitations due to stoichiometric ratios, reactants required in a biochemical pathway, or proteins required for transcription of a gene. Each of these k inputs is a strictly additive trait that depends on a set of common or rare variants. When k = 1, the LP model is simply a standard additive trait.[2]

First of all, this is A BIG DEAL.

Secondly, as with all unsolved mysteries of science (the ones they cannot sweep under the carpet), the solution is “just round the corner.”  Like fusion, dark matter, dark energy, the Younger Dryas stadial (climate), the “divergence problem” in climate proxies (which no longer show any correlation between tree rings and global temperatures), and also the origin of life.  The solutions to all of those are just around the corner.

Back to the missing heritability problem, note that nowhere is any real, solid explanation for it, only just around the corner suggestions in models.

It’s significant that “a person’s susceptibility to disease may depend more on “the combined effect of all the genes in the background than on the disease genes in the foreground”.

Why?  Ever heard of junk DNA?  Almost as soon as the Human Genome had been laid out geneticists were asserting that 90%+ of all DNA in our genome was “junk DNA” (useless crap) – instead of admitting that they didn’t know what it was for.  They had determined a handful of DNA segments that meant something, and to them the rest was just “junk.”  Oy vey.  Bit by bit that claim has been shown to be wrong.  But still there are huge swaths of the genome that are not known.  Hopefully scientists will stop saying “we know it all and the rest is bunk.”

Missing heritability is claimed in this headline to be solved:

Genomic detectives crack the case of the missing heritability (Feb 22, 2013)
Yet  what does it say in the text of the article?
new study by Princeton University researchers, however, suggests that missing heritability may not be missing after all — at least not in yeast cells…
…Although the search for heritability was successful in yeast, finding missing heritability in humans is far more complicated, Kruglyak said…
…The study sheds light on the role of nature (genetic factors) versus nurture (environmental factors) in determining traits and disease risk…
…Kruglyak said that one approach to finding the missing heritability in humans might be to apply genome-wide scans to large families, rather than focusing on large populations as is currently done.
In other words, the case is not cracked, and the heritability problem is still a problem, as Sheldrake said.

Don’t hold your breath.  The “Cracked” article points out that:

Researchers have detected about 180 locations in the human genome where small alterations in the DNA code can have an influence on how tall or short a person is. Nonetheless, these locations account for only 13 percent of the expected contribution genetic code has on a person’s height.

DNA just MIGHT have the answers.  (And might not.)  

At the same time, magnetic jars also might someday actually contain plasma and allow us to have fusion reactors around the globe.  But if you started holding your breath back when fusion reactors were first thought to be “just around the corner” you’d have held your breath for something like 55 years now.

And the concept that life might have begun 3 billion years ago with a lightning bolt hitting a bit of muck in a pond – that still would take an even longer 60 years of breath holding.

I keep rooting for science.  But it is amazing how they keep on doing the same things and expecting different results.  Someone once called that being insane.

Please, science, don’t be insane.  Look to see what wrong assumptions you have and then change your approach!

Sheldrake suggests some approaches, but he has a serious “cootie” factor because he doesn’t accept the reductionist approach of science as the only way to work, so even though reductionist approaches don’t work the refuse to go down the Sheldrake route.  There be lack of funding there.

So, at present, all’s the worse for science and its breath holding “just around the corner” solutions.


3 responses to “DNA Only Explains 5% (or 13%) of Inherited Traits – The Missing Heritability Problem

  1. Some of that “junk” DNA probably really is junk. I think some of it is just repetitive sequences which probably can’t carry much information. To carry information it would need to be more varied. That doesn’t go for all of it though.

    I have often wondered if the so-called “junk” actually plays some important role in orienting the molecule in three dimensional space, perhaps also a magnetic aspect to it.

  2. Nature is not into having useless stuff thrown in, not on the protein level, so I suspect and predict that even the repetitive stretches od DAN will have a purpose. Your conjecture is as good as any I have. We are SO new into DNA and genomic research, it is amazing that anyone can just pass ad hoc judgement on what is turning up. It boggles the mind. It’s like walking into a hotel looking for someone staying there and standing at the entry vestibule and deciding, “Well, let’s go. Nobody here.” I mean you CAME to find someone, and then you don’t even go to the front desk?

    You might enjoy reading Freeman Dyson’s “The Origin of Life.” Though nearing 30 years old, he points out what they don’t know – and though I keep my ear to the ground, I haven’t seen much progress in that direction.

  3. Not sure if you had a chance to see my most recent post but I am inclined to ward a viral origin of cellular life. Oddly I have never thought about a viral origin possibility until I started looking at some of the ways evolution works and reasoned that some of the same principles of assimilation and folding probably go all the way up from the molecular to the complex organism level.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s