Welcome back to Science Sundays! I hope someone out there is finding them fun and informative :) Feel free to ask questions or suggest future topics in the comments!
The first one is that there are very, very few instances where there is one gene for a single trait. And there are no genes that code for liking reality TV (even though I know plenty of people who'd like to blame it on that!). In reality, most genes are involved in helping shape many traits--in all honesty there are probably many traits that we don't even know a gene might be influencing! This is referred to as pleiotropy.
The opposite is also true: most traits are influenced by a whole bunch of different genes. (This is how we end up with all kinds of continuous variation--like height--where there aren't distinct categories.) There are a few traits that aren't (think about whether or not you have wet or dry ear wax--did you know there are different kinds? More info about that here), but most all traits are considered to be polygenenic, as in, influenced by multiple genes.
Okay, hopefully I haven't confused you too much yet! So, we know that one trait is often not under the control of a single gene, but what is a gene? Well, it is a stretch of DNA that codes for a protein. So, through the process of transcription and translation, a stretch of specifically pattered basepairs of DNA (specifically those adenine, cytosine, thymine, and guanine's) are going to be read in three-base packages to create a stretch of amino acids that will then fold into a protein.
What is a protein then? Well, they're the basis of our bodies and do all kinds of things. We can find them doing things like:
– structural support
Basically, the whole gamut of necessary things to keep us running! One cool thing about a gene is that there is something called alternative splicing that goes on--basically how a stretch of DNA is edited before a final product is made (even DNA has editors!). What this means though is that one stretch of DNA/gene can code for a lot of different types of proteins! The record holder for the total number of proteins that come from a single gene? 38k--in fruit flies! Cool, right?
Genes are vastly important, for obvious reasons, but we don't have as many as researchers originally thought. In reality we have around 25k genes (give or take, depending on the estimate). About the same number as a host of other species, ranging from really complex to super simple. So our true complexity doesn't lie in the number of genes we have!
I hope you found that interesting, and maybe learned something a little new!