The Latest on Genes
…”[G]enome-wide” surveys examine the links between a trait and all of the 20,000 or so human genes.
This has been an extraordinarily powerful approach. For the most part, what has emerged from these studies is evidence of the minimal extent to which some trait is “in your genes” and of how relatively unimportant any given gene is.
Height:
The single genetic variant that was most powerfully associated with growth explained just 0.4% of the variation in growth, and all the hundreds of identified variants put together explained only about 10% of the variation — which is not a lot of explanatory power.
Body Mass:
An equally acclaimed study used similar techniques to study body-mass index (BMI). After research on nearly 250,000 subjects, the genetic variant most clearly identified with BMI accounted for only 0.3% of the variation.
Educational attainment:
The most predictive single genetic variant accounted for 0.02% of the variation between individuals. Putting together all of the identified genetic variants explained only about 2% of the total variation.
Source: The Wall Street Journal.
“The single genetic variant that was most powerfully associated with growth explained just 0.4% of the variation in growth…”
Yet, we’ve all need big, tall men with big, tall sons — although extremes tend to regress back to the mean. I still find it hard to believe that height has no significant genetic component.
We’ve also seen attractive individuals with attractive offspring — whether male or female. However, many experts believe attractiveness tends to be a sign of good genetic variation.
I think that what this means is that a lot remains unknown. If the identified genes only explain a small percent of the variation, there must be some other “thing” that remains unidentified which explains some other portion of the variation. Meaning that science still has some unknowns to discover.
In the vast complexity that is the human body and genes, I am positive that there definitely more research that science needs to discover to find the other portion of the variation.
“The single genetic variant that was most powerfully associated with growth explained just 0.4% of the variation in growth, and all the hundreds of identified variants put together explained only about 10% of the variation — which is not a lot of explanatory power.” R^2 seems to be a little bit too low. More efficient and unbiased indicators are needed.
So now I can’t blame my mother and father for my short stature..
Or your lack of educational attainment either.
There’s an old saying… “the apple never falls far from the tree!” That’s another way of saying if your father was an idiot, there’s a good chance you’ll be one too!
I have a hard time believing some of this. I believe my eyes when two tall parents have a tall child or an attractive couple has an attractive child. Or even a thin couple having a thin child. I’d say I’m still a skeptic.
The question is then has the Human Genome Project has been a waste of time? I mean, we are talking about one of the biggest project in science history, which involved several hundred (even thousands) of scientists. The project that revolutionized how we think and that was going to bring answers. Yet, it seems that it raised more questions that what it answered. Normally, something that explains only 10 percent is something that is not very effective, so why do some consider this project as a success?
We have also to consider the importance of the gestation period on the babies. Even with similar genes, if the there are major differences during the mother’s pregnancy; chances are that the individuals will be very different. The problem with trying to explain these differences is that there are lots of variables we have to consider.
Epigenetics is the study of factors that trigger gene expression. Many geneticists think gene expression has more explanatory value that the mere presence of certain genes.
Instead of trying to explain what make us different, scientist should focus on the genes that carry diseases (diabetes for example). I believe those are easier to find and eventually science can find a way to prevent them or cure them.
Science does focus on genetic diseases. For example, by studying phenylketonuria the problem has been outlined, testing programs implemented, and a diet prescribed to prevent damage.
A important preventive measure, which many societies practiced before the development of modern science and has now been explained by it, is a ban on, or the discouragement of, consanguineous marriages.
But, as Buster pointed out, there’s reason to believe that genes are far from the whole story, and the biology simply is not well understood.
I question this research. If we cannot change the genes, why invest millions of dollars to investigate about them? That money can find better use in something that actually helps humanity.
To those who doubt these findings due to the prevalence of tall parents having tall children, I would just point out this doesn’t really matter- no one is saying genetics is playing no role- even if it is a thousand genes working in concert to produce “tallness”, you get all of those from your parents, too