Continuing Human Evolution

I think it is quite obvious humans are continuing to evolve, even though all humans belong to only one species, that does not mean we are not evolving. If I could pick only three examples of current human evolution at work, it would be the ability or inability to digest lactose, the mutation to resist infectious disease, and even having blue eyes.

Lactose tolerance is only a recent occurrence in human history within the last 10,000 years humans became able to continue digesting lactose after they were weaned off breastmilk. This trait is far more common in Europe than anywhere else in the world because of their domestication of cows. It would seem that Europeans continued drinking cow’s milk until they quite literally mutated to digest it. Fascinatingly at least three more independent variations of lactose tolerance developed in Africa none of which were from the European line of gene mutation. I wonder if the mutation is so different because East African’s would have been drinking more goat milk or if it was because dairy farming in general was not nearly so prevalent until colonial invasions of Africa? Yet another mutation of this kind happened in New Zealand when sheep farming became the dominant form of animal agriculture in the country. Even stranger to think about is lactose intolerance, which is now considered to be a recessive trait even though as recently as 10,000 years ago lactose tolerance after infancy did not exist in significant populations. Even today ⅔’s of the world’s population do not produce enough lactase in their body to digest lactose after age 5. Today the ability to digest or not-digest lactose as an adult can be determined by a genetic test of which nucleotides are riding on your lactase gene. I think this is a clear cut example of human gene mutation/evolution in which populations who consume tons of dairy mutate to be able to digest it and all other populations with access to more diverse food sources have no need for the higher rates of lactose tolerance and maintain their recessive genetic trait of lactose intolerance.

Infectious diseases continue to break through all the modern “cultural evolution” that humans are so proud of and remind us that we are subject to the selection pressures of nature just like all other specie on Earth. I think this is the most impressive example of biological evolution in action, the genetic mutations to resist diseases. The example cited in our lecture was of resistance to malaria, the same mutation that causes sickle-cell anemia, if only one copy is present confers resistance to malaria, one of the worst diseases still plaguing human populations. I was also thinking of the largest outbreak of Ebola in history that happened not long ago, and how carefully studied were a very small group of people who survived contracting Ebola or were simply not able to contract it in the first place. That was the fascinating part, there are many genes if mutated can confer resistance or protection against Ebola, these mutations are extremely rare in Europe, way more common in Nova Scotia and may be present in at least 15% of the population in Africa. There are even recorded genetic mutations in the genes that code for cholesterol in the body, or delete receptors on lymphocytes or bind and block receptor attachment by HIV, all of these mutations create resistance to contracting HIV/AIDS. For a species that wonders if it is still evolving we certainly have a stunning array of mutations to choose from that can protect us from/or entirely prevent some of the deadliest disease that exist in the world today.

The idea that humans are not evolving  simply lacks scientific rigor. I believe there is plenty of genetic evidence of recent and ongoing human evolution. I think of everyone I’ve ever met with blue eyes and that is another evolutionarily-recent genetic mutation in our species. I’m not sure there is even scientific agreement on what the advantage is of that trait but it has obviously persisted in our species as a form of natural selection, which is evolution in action. I think the human genome is evolving very slowly but the mutation of our genes is going very fast, this is a protective trait, like and evolutionary air-bag that I believe will protect humans from any harsh and sudden changes in the environment, giving (at least) some of us the chance to evolve and survive new and unforeseen natural selection pressures from our environment. Although I’d bet we’d have to colonize other planets in order to separate  our population enough to develop real separate species of humans, that would be so exciting but it would take quite some time and may not even work like that…

6 thoughts on “Continuing Human Evolution

  1. Hey Diana!
    I wanted to start off by saying great blog post, I found it super interesting. I really liked how you talked about lactose intolerance. I knew a little bit about that, but not all the details that you shared. For example, I did not know it is more common in Europe of that 2/3 of the population do not produce enough lactase past age 5 to digest lactose. I wonder if humans will eventually evolve to be able to tolerate large amounts of lactose by producing more lactase, because of the large amount of lactose that humans currently produce. I also did not know that there is a test now to be able to tell if someone is lactose intolerant, so that was really interesting to read in your post. I also liked how you talked about disease resistance and Ebola, because of how recently the Ebola outbreak was.
    Anyway, great job, I really enjoyed reading your post!

  2. Hello Diana,
    Thank you for your well thought out and written response to this week’s blog post regarding the ways in which humans are continuing to evolve and the biological, behavioral, environmental, or cultural traits that are evolving in humans currently. You made a number of excellent points throughout your blog post. Your mention of lactose tolerance as a recent development for humanity was quite interesting. I also agree that infectious diseases provide an excellent example of the ways in which humans are still evolving and mutating. Once again, great job on your blog post for this week.

  3. Diana,
    My favorite part about your post was probably the paragraph about lactose intolerance. I think that this is a great example of the way that humans have continued to evolve over the course of time. When I was younger I remember lactose intolerance being a rare thing and very few kids had it and now it seems like just about everyone knows someone who is lactose intolerant. This also made me think about the number of people that are now gluten free due to celiac or a gluten issue. For years this issue was limited and hardly talked about but now everything is labeled as gluten free. Its interesting to think that maybe after a few hundred years how our bodies will adapt to these needs.

  4. Hello,
    I am definitely in agreeance with you when you said that that there is a lot of genetic evidence that humans are evolving. As humans continue to develop, we are also growing in various ways as means of technology. Because of technological advances, humans are able to live longer specifically because of medications that aid in life expansion. It helps us to live a healthier and an extended life span, and with more discoveries the natural world can become better. Genetic mutations are one of, if not the most fascinating examples of biological evolution. Although medicine has become an aid that most turn, the ability to fight infectious diseases is remarkable. Your specific examples of the various diseases provided great proof that humans have evolved.

  5. Hello! Thank you for posting!
    I also find the ability (or inability) to digest lactose among humans interesting as well. I was also interested to learn from our lectures that there were particular groups around the world that developed that ability first – dairy farmers. That never occurred to me but it makes perfect sense!
    I think our genetic mutations that allow us to resist infectious diseases are fascinating. The human body truly is wonderful and this is one particular part of our evolution I am especially thankful for.
    The different gene mutations that seem to lack any real reason (like blue eyes) confuse me as well, but I suppose that’s just another part of being human that we are left to observe in awe and wonder without any explanation. Although I’m happy to be a part of just one race here on Earth, your idea of colonizing other planets which will ultimately result in many different species of humans, intrigues me!

  6. Hey Diana!
    Really enjoyed your incite on the Ebola disease resistance. I remember last year when that outbreak was all over the news. The disease and prevention board did not know how to contain the disease or how it was spread. I remember the large populations of Africans that died from this horrific disease, not to mention the side-effects of the disease. However, like you said, there were survivors who beat the disease. These survivors may have the mutation needed to fend off this terrible disease. Its amazing how the human body will quickly develop mutations to protect future generations. With the improvement of current technology it can help create and improve the ability of mutations to develop and protect modern humans. The faster and more efficient ways technology can aid in developing mutations in humans, they will be able to overcome future diseases.

Leave a Reply