Blog Post Module 4
First of all, in order to know whether or not mutation rates evolve, one must first recognize Darwin's postulates: (1) Individuals within species are variable; (2) some of these variations are heritable; and (3) individuals that reproduce the most are those with the most favorable variations. I am mostly restating these postulates so I do not forget them when I writing, not because I think you guys don't know what they are. Anyways, back to the main point. My first instinct tells me that mutation rates cannot evolve. Instead, certain mutations become more common because they benefit the individual's fitness and nature simply selects for them. However, after further research, I have found that mutation rates can indeed evolve, especially when a cell is under extreme amounts of stress. This stress can cause the DNA repair mechanisms to undergo damage, which leads to more mutations. In addition, mutation rates can evolve within a population if there is a high amount of inbreeding. I remember Professor Tobler talking about how inbreeding occurs very frequently within the population of Cave Mollies due to their limited carrying capacity in the small habitat they live in.
I'm not gonna lie, I have read the second question about 10 times and still do not understand what it is asking, so I am going to answer what I THINK it is asking.
Mutation rates can adapt depending on specific environmental conditions. For example, as I mentioned above, inbreeding increases the risk of disorders caused by recessive genes. This is because animals must have two copies of the recessive allele in order for the phenotype to be expressed, and the more an organism breeds with similar genetic makeups, the more likely recessive mutations become activated. The environmental conditions that could lead to inbreeding include limited carrying capacity and space in the habitat. Another factor that could disrupt replication machinery and cause mutations is limited resources, such as food and shelter, within a population. These are factors that lead to stress and the more stress an organism is under, the more likely mutations can occur. Whether or not these mutations are beneficial for the organism can only be determined by how its phenotype interacts with the environment.
Works Cited
- https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(00)02085-1.pdf
- https://www.lic.co.nz/products-and-services/artificial-breeding/inbreeding-and-recessive-genes/
- https://elifesciences.org/articles/22939
Hi Casey,
ReplyDeleteWell you have pretty much summed up exactly what went through my head as well. I was confused about the question but also then I assumed they couldn't evolve and quickly learned they could evolve. I think the point you brought up regarding inbreeding is very important, if the population can evolve and mutate to avoid inbreeding, I think its essential that the population mutates at a fast rate. Understanding and studying the phenotypes is an important factor, and it makes us actually able to study mutations effectively. Mutations are so complicated and when thinking about real world examples, like cancer, it makes us realize how important it is to truly understand issues revolving around mutation.
Casey,
ReplyDeleteI am so glad that you were honest and personal with your blog post because I too was really lost when initially looking into the questions! I liked how you connected the first question back to cave mollies because it's an example that the whole class is now familiar of because of our exposure in the R exercise. I'm glad you mentioned the part at the end that mutations being beneficial depends on the phenotype reaction because I know it's easy to get caught up in if mutations are good or bad, but it's important to remember that sometimes it's neutral.
Hi Casey!
ReplyDeleteI think it is great how honest you were about the second question because I also was thrown off by it for a second! I really like how you explained your thoughts in this post, you made it very easy to understand! It's awesome to see that you consulted outside resources in this post and were able to incorporate them into the blog so that the rest of us can learn a little bit more as well! The information you put in here actually helped me to understand a few things better, so thank you for doing a great job!
I don't really have much more to add to the above comments - I appreciated how you broke down the question and showed the process that you took to think through it!
ReplyDeleteI think your approach to trying to answer a question you didn't understand is amazing! You took what you did not know and learned from it. Keep doing what you're doing, I can tell you are learning!
ReplyDelete