It's no secret that height is an inheritable trait...
Tall parents often have tall children. Short parents often have short children.
There are even formulas, some used by doctors, that can predict a child's height based on the height of his/her parents. This is a popular one:
- 1) Combine the mother's height and father's height in either inches or centimeters.
- 2) For boys, ADD 5 inches (13 cm) to your total. For girls, SUBTRACT 5 inches (13 cm).
- 3) Divide your new number by 2 and you have a child's predicted adult height.
Got kids? Try it out and see how well it works.
While everyone knows that a person's height is influenced by DNA, what hasn't been known is how... Until now.
A study recently published in Nature found 12,111 single nucleotide polymorphisms (SNPs) connected to someone's height.
If you've been around CRI Genetics for a while, you might know that "SNPs" are just genetic variants that help determine many of our individual traits. If you're new here (or new to the concept of SNPs), you can learn more in one of our older helpful blog posts.
For the study, researchers tested the ENTIRE genome (that's ALL of a person's DNA) of 5.4 million individuals.
That's a whole lot of DNA... Needless to say, this was a multi-year effort that required contributions from hundreds of scientists all over the world.
Despite the GIANT scale involved with the study, the work itself was relatively straight forward. Height is easy to measure and we already know that it's influenced by DNA. Getting results was a relatively simple, yet time-consuming effort of finding correlations between the two.
As with many genetic traits, there are environmental and lifestyle factors that can influence a person's height. The most obvious example is diet -- a lack of certain nutrients in a child's diet can stunt his/her growth.
By studying such a large amount of DNA from such a large number of people, it helps limit the impact of these other factors on the scientists' discoveries.
Now I know what you're wondering...
Is the next CRI Genetics report going to be about height??
Well I'm a "never say never" kind of guy, but we prefer to limit our reports to a handful of SNPs at most. I may take some heat from our Science team for writing this, but I think those 12,000+ SNPs need to be narrowed down a bit to determine which ones are most important before we try to create a "Height Report."
I definitely won't take heat from our Science team for writing this: More research is needed on the genetic factors involved with height anyway.
More research is especially needed because there were some flaws with the study. A couple such flaws include the fact that the vast majority of participants were of European ancestry and that many of the genetic links for height discovered only work for people of European ancestry.
The researchers themselves admitted that their findings would benefit from further study with a more diverse group of people. It would be especially helpful to include a significant number of people with African ancestry, as there is more genetic diversity among people with African ancestry than among all other populations.
Unfortunately, it will likely take several more years of study before a DNA-based predictive model is created that can reliably estimate a person's height.
But progress is progress. This is often how it is with science. This study was a ground-breaking step in the right direction.