Who knew this would become a mini series! Well here we go with part three. Today I want to talk just a little more about our genes and how they are expressed, and what implications we can (or cannot!) draw from that information.
If you had time to watch the TED Talk that I linked here last week, or if you remember studying this before, you know that our genetic code is written using four different bases that pair up within our DNA’s structure - Adenine, which always pairs with Cytosine, and Guanine, which always pairs with Thymine. These base pairs are arranged and fitted together to create sequences that can be “read” by our RNA and used as a blueprint to build each of our cells. This means that each trait you possess can be traced back to these base pairs and the particular order in which yours were arranged. As we saw in the video last week, typing out just the first initial of these bases into a book for one person’s entire Genome takes roughly 175 very large books with no spaces. It’s more information than any computer can hold! That’s a massive amount of information stored in our DNA by these base pairs!
The reason it’s important to dig into this information is because understanding this helps us see that there is no binary within our genetic code- there is no base pair that is an opposite of another. A person with blue eyes doesn't have the “opposite” of someone with brown eyes. This is true of skin color, of the length of your nose, or the shape of your ears. There is only a spectrum, with traits being expressed more strongly or less strongly.
This is a moment when I would also like to touch on something we’ve discussed here briefly before - That our biological sex operates this way as well. There are two larger categories that we are taught about in our junior high biology class. We were taught that if you have two X chromosomes (XX) then you are female and if you have one X and one Y (XY) then you are male. But in reality there are also other possibilities, such as XXY and XYY, that are considered atypical. These genes may be expressive or they may be hidden.
In addition to these chromosomes there are other characteristics that are considered when determining a person’s biological sex. Right now when a child is born, the individuals present usually make a visual determination based on the baby’s genitals, but we know that this is not always an accurate indicator of what’s happening on a cellular level, a hormonal level, or a personal identity level. Secondary characteristics like the presence of facial hair, height, and a deep voice have long been considered an indication of being male, however there are women and non-binary folks who would break each of those stereotypes.
Individuals who have these chromosome pairings or who have ambiguous sex characteristics can be considered Intersex individuals. This may include individuals who were assigned female at birth, but they can grow beards. Or someone assigned male at birth who produces little testosterone. This also includes folks who have ambiguous genitalia, which does not fall into the simple two categories we’ve been trained to view as “normal.” We are finally starting to see places like Germany consider adding an Intersex option for birth certificates and drivers licenses.
There are mountains of information on all of this that we don’t have time to add here but I hope these newsletters have helped shed some light on these complicated and broad ranging topics. My hope is that this discussion has prompted you to sit with your own beliefs about binary, spectrum, about gender, and everything we as humans have in common.
Once more, Here is the link where you can watch his full TED Talk if you’d like to dive deeper into the fascinating world of genetic sequencing!
Thanks for reading!
--Charleston Andrews