Now with this being my third blog post, I wanted to find a more personalized topic that relates to me. After all, this is a blog post about biochemistry which is the study of how chemistry relates the living organisms and I do believe that I am a living organism. So, I thought to myself what was the most interesting science related thing about me (that wasn’t videogames because I couldn’t find any research on what kinds of chemicals are released in the brain when playing video games) and that turned out to be my extra thumb that I had on my left hand that I had from birth to when I was one year old when I had it removed. I hope after reading this post you (and myself after researching this topic) will have a better chemical understanding on how this came to be.
So what is polydactyly and what’s the deal with genetic mutation? During normal embryonic development, the hand initially forms in the shape of a paddle, and then eventually, in about the sixth or seventh week of gestation, splits into separate fingers. Polydactyly results if there is an irregularity in this process. An extra finger forms when a single finger splits in two. The vast majority of occurrences of polydactyly are sporadic, meaning that the condition occurs without an apparent cause, but some may be due to a genetic defect or underlying hereditary syndrome. African-Americans are more likely to inherit the condition than other ethnic groups. Polydactyly is an inherited through a dominant allele of a gene. Or it can be caused by a mutation of the GLI3 gene which is responsible for tissue patterning and organ development.
A change in the DNA, such as during development in this case, is called a mutation. A change in the base sequence of DNA that is then replicated and transmitted to future generations of cells becomes a permanent change in the genome. Mutations, all of which appear to occur as random events, can range from a single replacement of a base to a larger change that results from the deletion or addition of more than one base. Most mutations are thought to be harmful to the life of the cell. These harmful mutations occur during the development of a cancer cell, for example. In these cases, numerous point mutations or deletion are well-established as causative agents. A point mutation occurs when a single base is changed in a DNA sequence. This can either be a transition, in which a purine base is replaced by another purine base, or a pyrimidine by a pyrimidine. This can also be a transversion, in which a purine is replaced by a pyrimidine, or vice versa. A point mutation that changes a codon with the result that it codes for a different amino acid is called a missense mutation. Mutations may occur spontaneously, or a result of external physical agents (radiation) or chemical agents (mutagens). The most common spontaneous mutations result in DNA replication errors. Another common way mutations can occur are when a life form is exposed to ultraviolet light from the sun, which can react with adjacent thymine bases in DNA. A number of chemicals, including dimethyl sulfate, nitrous acid, and nitrogen mustards, react with bases in DNA so as to modify them.
If you cared at all about my personal experience with having this birth defect, I will share some of my insight on what it’s like to live with this thumb of mine and what I have learned about it over the years. When I was born with my extra thumb, I was not eligible to have it surgically removed until I was one year old. It was my parent’s decision to have it removed although if it were up to me, I definitely would have kept the thing. Imagine the possibilities. Anyway, I got the thumb removed at Scottish Rite Hospital for free but in return I would have to return to the hospital every four years to contribute to an international study where they would run a series of physical tests on my altered left thumb and ask me personal questions about my academics, sports, and hobbies. Going and doing the physical portions of these tests, I realize how weak my thumb actually is compared to my normal right thumb when it comes to pushing, flicking, or bending. The doctors that have been conducting the study have told me that there is some correlation, or trend, in those who were born with an extra thumb and how involved musically they are. I don’t know or even know if the doctors know if there is any kind of science that is related to that trend but it is something they have noticed. I am supposed to go back every four years and this year, me being 17, marks another 4 year marking period. If I am asked to go back for more tests, perhaps I will not forget about this blog post and come back and update it.
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