Jeff wrote a blog post about recent advances in technology, their affect on our daily lives, and subsequently what it means to be human. He wanted some examples of external factors playing an integral role in human biology as part of the larger argument. From these musings we are thinking of doing a two-part Barcamp talk on Transhumanism. Part 1 will be biology and part 2 will be technology.

The following sections cover three notable examples of external factors that help make up the human body.

Human Flora

Human flora is the encompassing term for all microorganisms living symbiotically in our body. These are various species of bacteria, fungi, and archaea that live in our gastrointestinal tract, saliva, oral mucosa, and even on skin. Some of these organisms help digesting, breaking down complex chemical compounds that our intestines can’t digest. Others are not so beneficial, such as the bacteria that cause plaque and teeth decay. Many of these species have no known effects, but some can cause disease in individuals with compromised immune systems.

Bacteria are small and can live in a huge variety of environments, so it is not surprising they get into and onto our bodies. It is estimated that our bodies are made up of ten times as many microorganism cells as human cells. Another interesting fact is that babies are not born with any of these microorganisms but very rapidly acquire them from eating and… well, simply existing in this world. These bacteria that have co-evolved with mankind are very much a part of our bodies.

Viral DNA

Many viruses reproduce by invading a host and using a viral protein, reverse transcriptase, to make viral RNA into DNA. The viral DNA then can get incorporated into the host DNA, causing the host to make viral proteins. However, sometimes errors occur and the viral DNA gets inserted into the wrong place and does not replicate the virus. These regions of DNA are a part of “junk DNA”. They are completely useless foreign DNA, but because there is no selective pressure, there is no reason for it to leave.

Transposons (also known as jumping genes) are also thought to have originated from viral DNA. These are “junk DNA” elements that seemingly move from one location to another. The way this works is that the DNA gets transcribed into RNA, but then a reverse transcriptase (usually found on the transposon itself) makes the RNA back to DNA. The new DNA randomly incorporates itself into a new location.

While these examples are completely random additions of non-functional DNA that seem meaningless, they actually serve some function for our genetics. First, they are spacers that separate regions of important DNA to allow space for certain proteins to bind. Second, it provides diversity between different people and allows more diversity when passed on to a child. Diversification of DNA, after all, is an essential part of evolution.

Sickle Cell Anemia and Malaria

Sickle cell anemia is genetic disorder highly prevalent in Sub-Saharan Africa. It is caused by a single point mutation that cause red blood cells to have a sickle or half moon shape. Normal blood cells are circular disks that can easily slide across each other. Sickle cells, however, clump up and can easily clog blood vessicles, which can be fatal, oftentimes before the individual can reproduce.
Then, why is this mutation so prevalent? Turns out that carriers of this disease (who do not have the disease themselves) are resistant to malaria, another prevalent disease in the area caused by a parasite and carried by mosquitos. If two carriers mate, there is a 25% chance of the child getting sickle cell anemia, but 50% chance of being resistant to malaria. Hence, the selective pressure of malaria has caused sickle cell anemia to be more prevalent than it would have been otherwise.

Conclusion

I have covered three examples of how human DNA has been affected by our environment and evolution. Despite the perception that our body is a single entity, there are layers and layers of underlying complexity. Some of this complexity had been co-evolved with other organisms, viruses, and genes (especially those selfish ones).

Sources: random things I remember from biology classes, Wikipedia.

Since I’ve stopped using Facebook (for various social reasons that I am still organizing my thoughts around and will eventually come around to posting those reasons), I’ve noticed a drastic increase in my Engagement Rank for Twitter. The two are directly related. It says “I’m a key member of the community”!

Engagement Rank analyzes your twitter feed and statistically determine a score based on your interactivity with other users. On one end of the spectrum are people who only absorb information and on the other are people who respond to everything. I use to be on the former end, but seem to be moving more towards the middle.

The real question is what does your engagement rank tell you? Are you to have a higher quality of life? Aren’t you just as likely to receive information without engaging? You can definitely form stronger interpersonal relations. In general, it parallels how social you are. Being an introvert, I’m going to be on the lower end of the engagement rank. However, some introverts can be extroverts online due to the nature of communication and the ability to take time to consider and conduct a response.

I’ve been doing some social experimentation and philosophizing recently, especially focusing on real-world versus internet social interactions. We’ll see what conclusions I find…

IgniteLA was this past Monday and to my surprise, Frances Arnold, CalTech professor, gave a talk. This is surprising, first, because I am shocked by the quality of people/talks (as compared to IgniteSD). Secondly, she is highly regarded in the field of directed evolution, which is a part of my research. It is awesome that she did an Ignite talk on it. Hence, I had to share the video for those who want to know more about my research. Video was taken by @tv.