Have you ever heard of the circadian rhythm? It is a biological clock inside our body that is responsible for controlling internal activities, such as regulating protein transcription, which greatly affects metabolism. The circadian rhythm works closely with daylight, it upregulates protein transcription during the daytime and represses transcriptions at night.
As night owls, people including myself, find that we work best late at night and appear drowsy in the morning. One explanation for this is the delayed sleep phase syndrome (DSPS), a condition that lengthens the biological clock and makes our circadian rhythm run later than those with a normal schedule. When night owls fall asleep later at night (or even early morning), we still have to wake up for school and work, which could lead to insufficient amount of sleep and possible insomnia in the long term.
Interestingly, scientists have suggested that there is a type of mutation that would lead to people being night owls and experiencing DSPS. Normally, we have four important proteins that regulate our biological clock, CLOCK, BMAL1, period (PER), and cryptochrome (CRY). The CLOCK and BMAL1 proteins bind together to form a complex that upregulates the transcription of CRY and PER protein during the daytime. At night, as the concentration of CRY and PER increase, they bind together and move into the nucleus where they would interact and act as a suppressor for the CLOCK: BMAL1 complex, halting further transcription. The PER: CRY complex is broken down by enzymes overnight before the CLOCK: BMAL1 complex is freed to transcribe more PER and CRY in the morning. The whole process of building up protein concentration and breaking down the complex usually takes 24 hours; therefore, our circadian clock coincides with our 24-hour sleep-work schedule.
However, when there is a mutation, specifically deletion, that happens in the region coding for the CRY1 protein, the tail part of the protein got cut off, which increases the affinity of the protein to the CLOCK: BMAL1 complex (Parico et al., 2020). The stronger-than-normal binding between the cryptochrome protein and the CLOCK subunit in the CLOCK: BMAL1 complex makes our circadian clock lengthen each day.
References
Parico, G. C. G., Perez, I., Fribourgh, J. L., Hernandez, B. N., Lee, H.-W., & Partch, C. L. (2020). The
human CRY1 tail controls circadian timing by regulating its association with CLOCK: BMAL1.
Proceedings of the National Academy of Sciences of the United States, 117(45), 27971. https://doi-org.dml.regis.edu/10.1073/pnas.1920653117
Sahar, S., & Sassone-Corsi, P. (2009). Metabolism and cancer: the circadian clock connection. Nature
Reviews Cancer, 9(12), 886. https://doi-org.dml.regis.edu/10.1038/nrc2747
It is super interesting to see how being a morning person or a night person may be due to a genetic mutation rather then a preference over time of day. I wonder if there is any lasting effects of having ones circadian clock lengthened. This article says that when our circadian rhythm is disrupted it can cause decreased alertness, memory problems and difficulty with decision making. It seems like with this deletion the circadian rhythm is disrupted and the sleep-wake cycle is not constant which means that night owls are not getting adequate sleep. I wonder as well since the world works on a schedule of working during the day and resting at night, it further impacts night owls due to the inability to rest during the day.
ReplyDeletehttps://www.nhlbi.nih.gov/health/circadian-rhythm-disorders#:~:text=Circadian%20rhythm%20disorders%2C%20also%20known,cycles%20about%20every%2024%20hours.
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ReplyDeleteWhile I have never considered it, it makes sense that night and sleep habits are affected by genetic make up. However, I also wonder if your sleep behavior encourages your gene expression to appear this way. Your sources claim that the determination of being a night owl or a morning lark could be genetic, but it is also important to note that you are likely raised in an environment that caters to your parents sleep schedule. Because of this, I would assume that as you are developing as a child, your body does its best to adapt to its environment. This could mean that it changes its gene expression for CRY 1 proteins to have their cut tails, because your body wants to fit into its environment and follow the patterns that your parents have set. If your parents stay up late, you will want to too and your body will do it what it can to make this possible. I would be interested to see if children who had later bedtimes growing up developed this genetic make up compared to those that had an early bedtime despite their own parents habits. I found this article that works to support this idea and shares how influential behavior can be when the body is working to express certain genes. Your post was very interesting. Thanks for sharing!
ReplyDeletehttps://jackwestin.com/resources/mcat-content/biological-bases-of-behavior/influence-of-genetic-and-environmental-factors-on-the-development-of-behaviors#:~:text=Behavior%20can%20influence%20genetic%20expression,early%20as%20the%20prenatal%20period.
Super interesting study. I definitely have noticed a pattern in my own family of some, but not all, of us being Night Owls. What I would love to see is a genetic vs. environmental study regarding this mutation and circadian rhythms to see the relationship between nature vs. nurture in causing individuals to be "Night Owls".
ReplyDeleteI think this is a very interesting idea to study, especially seeing as in my family my brother and I are night owls while our parents and other brother are all early sleepers and morning larks. I think JackM618 has a really interesting study in mind for genetic vs. environmental factors and how each of those can contribute to our sleeping patterns. It would be interesting to see if one has more impact on the other and even if someone has the genetic markers of a night owl, if living in an environment that is more prone to being a morning lark how that could effect them.
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