So yeah, I am that dude who was complaining about my height and my parents got a genetic test for me done on 23andMe. I had to spit in something and it was shipped off to be examined. I am a 16-year old guy and 5’3.5 and my parents are 5’7 and 5’0.
So I got my test results and I was looking online to see which gene controls human height. They say it’s this gene called “HMGA2”. So I type that into the gene search bar and it tells me:
For 1 of them, my dbSNP Orientation is “minus”, and for the rest 20 of them, it’s “plus”. What does this mean?
So these were my results (the far right is what I have)
The first one is the “minus” one. The rest are “plus”.
I don’t know what this means. Can you guys help me interpret this if you know how genetics work? I was reading that you’re taller if you have more C than T on some article online, but what is A and G?
And for some reason, it’s making hyperlinks but you won’t be able to access them because you would have to log in to my test results, so just ignore them.
This tells us nothing unless you know which genotypes are associated with height. You have an AA genotype for the first one, for instance. But that’s not informative unless you know whether AA or CC is more commonly seen in tall people. Etc, etc.
Update: I was researching online to see which SNP’s controls human height. They say there are three SNP’s that are major determinants of human height:
[ul]
[li]rs1042725 (for this SNP, C means tall and T means short)[/li][li]rs7968902 (for this SNP, T means tall and G means short)[/li][li]rs7968682 (for this SNP, G means tall and T means short)[/li][/ul]
Well guess what? I got all the short genes! For rs1042725, I got TT! For rs7968902, I got GG! For rs7968682, I got TT! Fuck…yep, so much for having a late growth spurt…I will be forever short…
That being said, this is being done for my naturopathic doctor and he was basically saying that based on my genetics, if one of the genes “isn’t working” (for example, one of the height ones is not functioning properly), he will substitute it with supplements. So maybe there’s some hope that he will be able to help me out a bit…if something isn’t functioning properly…
I know I am going overboard and being quite pedantic with this whole height thing but genetics is actually something that interests me, and something I might consider going into for my career. So that’s why I am really digging into this. And look what we find…
If you are really interested in the genetics I can’t offer any info other than I read that eventual adult height is 80% genetics and 20% environmental.
If you want to keep it simple, there are several ways adult height is predicted. If your parents know how tall you were at age 2, just double that. Another way is to take an average of your parents’ heights and add 3" to that ( because you are male. A girl would subtract 3").
The averaging predicted my exact height. However, my sister grew about 1 1/2" taller than me.
As a geneticist and fellow short person, I’m about 5’3", I don’t think these results are anything to get worked up about. Looking through that paper, those three SNPs account for about 3% of the variance in height. What that means is, for any two people about the 3% of the reason they are different heights is due to differences on those three SNPs. The total height difference between somebody who has the increasing alleles (the version which makes the trait bigger) and somebody with the other versions is probably an inch or less.
Of course, all of that is assuming that the results are correct. Nothing jumps out at me as being wrong with what they did, and it’s not much of a stretch to imagine that different versions of the HMGA2 gene, which is thought to be associated with body size in mice, is related to height in humans. There is however no indication of what change in the gene actually causes the difference in body size. Maybe other research has sorted it out in mice, but I’m not doing a lit review. It could be a change in the protein produced from the gene, it could be the amount of protein produced, or it could be something else extremely complicated we don’t understand. That makes it unlikely that something could be taken to behave like the increasing version of the gene.
I am sympathetic; being a short guy ups the difficulty level of life. But, based on the height of your parents it’s not at all surprising that you’re short. I wouldn’t put too much focus on these results though. When I was your age human growth hormone treatment was extremely experimental, and I never bothered to keep up with the research. It’s my understanding though, that once the growth plates on your bones disappear there’s no easy treatment to gain height. There’s this thing where they break your legs and let them heal longer, but no. Anyway, I’d say see a proper medical doctor who specializes in height stuff.
My only other advice is to try and date girls who have short fathers. They seem to be less disturbed by short guys. Also, people will call Tom Cruise (5’7"?) short. Try not to punch those people in the nuts.
A quick primer: HMGA2 is the gene. Cool sciency stuff happens to it, and then protiens get made. Single nucleotide polymorphosims (SNPs) are base pairs which are known to vary in the population. For a particular SNP some people will have TT, some TC, and some CC. HMGA2 will have several places in and near it where there are SNPs. Any particular SNP is probably not the cause of the change in the trait, but may be associated with whatever does cause the change. Association is both the name of analysis used, and a good way to think about it. You are associated with your sister, but you are not your sister. Because you are associated, if I find you, there’s a good chance your sister is nearby.
Where can I find the list of SNP’s that account for the other 97% of my height? Because if I know the other SNP’s, I can simply type them into my chromosome thing and it will tell me what I got.
We don’t know all of them by a long shot. This paper suggests that ~45% of height variance can be accounted for by considering 294,831 different SNPs. For comparison, they mention that ~80% of all height variance is due to genetic factors. Their approach does not identify which individual SNPs are contributing to height. That requires a different approach to avoid false positives which are hard to avoid when analyzing genome-sized data sets.
I have nothing to add about genetics, but when I was a teenager I was short, fat, and had a small stubby penis. I couldn’t imagine even attempting to date or have any kind of sex with anyone. By the time I (mostly) stopped growing around age 19, I was 6’ and muscular. If you go by the various penis size surveys that appear to have some legitimacy, I am in the top 1% or so in length and somewhere in the upper 50% in girth. I had a friend who was under 5’ when we started high school. He ended up around 6’3 and has short parents.
Just anecdotally in my observation of parents and their children the mother’s height (for whatever reason) seems to have more influence overall on final heights in children than the father’s height. In other words if you have a tallish mother and a medium height father vs a medium height mother and tallish father the tallish mom+ medium height dad combo always seems to result in taller kids overall.
So echoreply, you’re saying that despite those three SNP’s trolling me, there’s still a slim chance that for the other hundreds of thousands of SNP’s, I have the tall genotypes and therefore still may have a very unlikely chance of not being a manlet for life?
First, being even shorter than you, I take offense to the term “manlet”. And so should you ! Despite what you may WANT, there are some things you just can’t change. So it is far better to just accept the things about yourself that you can’t change, and make the best of it.
But as to the 3 SNP thing, I believe there HAS to be many more factors involved in determining your eventual height. One way to look at it: if the 3 SNPs were the ONLY factors, there would be a total of only 27 different heights across all people ! That is, if you took, say, all the people attending a football game one day, and sorted out all the “adults” (say between 30 and 50), they would all fall into exactly 27 different, discrete heights. I don’t think so.
