53 upvotes, 4 direct replies (showing 4)
View submission: How do genes get passed down?
Your DNA gets inherited in the fashion you describe, where you will randomly get genes from either one of your parents. However, genes don’t map onto the type of anatomic traits that you’re interested in very well. That is, there is not a single gene that determines the shape of your nose, or even a small part of your nose. Because development is really complicated, the interplay between genes is also super complicated. That’s why we don’t tend to have noses that look identical to either one of our parents, but instead have our own unique look that can be more or less similar to one of our parents.
Height is another great example; even though it seems simple, it’s determined by many hundreds of genes at least. You inherit those genes from your parents, yes, so it’s likely that if both of your parents are tall you will also be tall. However, if you are male, your father is 1.9m, and your mother’s father is 1.6m, you could be pretty much any height, not only 1.9m, 1.6m, or the average of 1.75m.
Not sure if I’m making sense or not. There are about 20k genes so in terms of the unit size of genetic inheritance it’s in about 0.005% increments, but you can’t easily map each of those 1:1 with an observable trait.
Comment by mrpointyhorns at 24/11/2024 at 02:46 UTC
9 upvotes, 0 direct replies
With height up 20%-40% comes from enivornmental factors too. In the US, it's about 20%.
You can predict the height of someone using equation herehere
Comment by cthulhubert at 24/11/2024 at 04:10 UTC
6 upvotes, 0 direct replies
20 thousand *coding* genes, with that many again non-coding genes, many of which perform regulatory functions, that could include changing how active any given set of coding genes are.
Comment by jombozeuseseses at 24/11/2024 at 00:15 UTC*
6 upvotes, 0 direct replies
One thing to note is that there are many genetic sequences that express clear phenotypes independent of other genes. But most things to do with physical appearance are not so!
Comment by Justmyoponionman at 26/11/2024 at 18:15 UTC
1 upvotes, 1 direct replies
Also genes come in packages. If two genes come from the same chromosome (single strand of DNA) they cannot be inherited separately. They are linked. People generally have 46 sorted into 23 pairs. Of each pair, you inherit one from each parent.