Showing posts with label genetic analyses. Show all posts
Showing posts with label genetic analyses. Show all posts

Friday, March 19, 2021

Bug Warfare Woes—Part 2

There is another way to deal with the invasions of microorganisms that promises a far more effective approach to dealing with various diseases caused by bugs. Rather than go to war with them, we could engage with them in positive ways that disarm them, and then live with them. This approach does not force them to become more virulent and fight back. This is a smarter, nonviolent approach.

We have already used this approach in developing vaccines. The process of creating many vaccines is to cause the harmful microorganism to evolve into a milder form in a laboratory, which we then inject into people. As a result, a person develops immunity to that milder bug (that we have literally bred) as well as the more harmful one, without getting sick. There is no attempt to kill off the microorganisms; instead, we disarm them (make them less virulent) and then live with them by building immunity. This is a way of duplicating how we naturally encounter many nonlethal kinds of bugs, which do not do us much harm at all—such as the rhinovirus that causes the common cold (which is a distant cousin to the SARS-2 virus that causes COVID-19).


This is how we can come to live with organisms that hardly make us sick—by transforming them into less deadly mutations. Many of the viruses and bacteria that invade us really have no intention of causing us serious harm. All they want to do is breed, multiply, and flourish—just as all life does. If they can do that without sickening us, that would be fine with them. In fact, our health can be important to their well-being… if we die, they must quickly find another host before they too expire. 


They are, however, in constant competition with other kinds of microorganisms (sort of a bug arms race), so they try to reproduce in huge quantities. That sometimes causes them to get out of hand, or evolve into extremely virulent bugs that cause diseases such as malaria, cholera, typhoid fever, dysentery, smallpox, tuberculosis, and others.


We now have the science to characterize the genetic makeup of these microorganisms. This knowledge can help us to control their evolution and transform them into weaker, rather than stronger mutations. The fact that they mutate so fast, means that we can alter their genetic character in just a few weeks. When we do so, we need not go to war with heavy weapons that cause them to fight back. We can earn to live with them!


Furthermore the weapons we use to fight microorganisms (such as antibiotics) often cause lots of collateral damage when they also harm the trillions of beneficial bacteria that inhabit our bodies. Thus, after a dose of powerful antibiotics that has wiped out both the bad and the good bacteria, we must then use probiotics to recolonize our gut system with beneficial and necessary bacteria. 


We have the capability to make that transformation to a peaceful coexistence, if we forgo our natural instinct to go to war with every bug that we meet and learn to live harmoniously with them.


Tuesday, July 23, 2013

Our Denisovan Cousins



The July issue of National Geographic Magazine describes an amazing story of the recent discovery of yet another species of our human family that went extinct tens of thousands of years ago: the Denisovans. Remarkably similar to the Neanderthals, the Denisovans were a human subspecies that left Africa long before our species Homo sapiens did. They spread fairly widely throughout Eurasia and then died out. And, like the Neanderthals, they left traces of their DNA in us modern humans. In other words, our human ancestors seemed to be attracted enough by these extinct cousins of ours to have interbred with them, which finds us continuing to carry around a little of their DNA.

I find the story of human evolution fascinating. The narrative has been spectacularly amplified in recent years through evermore precise genetic measurement tools. Where anthropologists were once confined to detailed examination of the shape and appearance of fossil skeletal remains, they now can perform exacting genetic analyses of the tiniest of bone fragments.

Before 2008 we were completely unaware that a subspecies like the Denisovans even existed. Their population appears to have been rather small and no identifiable bone fragments had ever been found. Then, five years ago, digging in a cave that had repeatedly been used by people over the eons, a Russian archeologist discovered a miniscule bone fragment in a Siberian cave called Denisova. Had the discovery been made just a few years earlier, it is unlikely that this wee fragment would ever had led to the realization that it was from a previously unknown prehistoric species of human. 

Cutting-edge DNA analytical methods that have recently been developed in Germany (Max Planck Institute) were able to construct the complete genome of the person from whom the bone fragment came: the left pinky finger of an eight-year-old girl. (They even got a pretty good idea of the color of her hair!) In fact, these techniques have become so precise that the girl's genome could be probed to the extent that researchers could even describe the different genetic contributions she received from her father and mother. From a bone piece the size of a dried bean!

The speed with which our evolutionary history is being filled out is astounding. Scientists are discovering that our origin is far more complex and rich than we'd ever have guessed. Anthropology is as exciting a field as cosmology these days, as the rate of new discoveries is so great that specialists in these fields have a hard time keeping up—let alone us average beings.

It makes me wonder about the even better research tools that will very soon become available, and the wonderful stories that they will reveal about the nature and origins of our universe and all its marvels. I am getting perilously close to my 73rd birthday, which causes me to increasingly reflect upon my mortality and how little time I have left to learn about all these neat things. At my age I take great comfort in knowing that the pace of discovery has picked up as much as it has. Hasten on, science!