Evolving Less-Costly Evolution Models

Theoretical models and computational ability has long been a cornerstone of science. One of the ways many fields are advanced is to utilize these ever-expanding tools in order to make new predictions and simulations that can then be tested in the real world. For example, in the nuclear physics lab where I work, the theorists are constantly tweaking equations – or even creating new ones – to better describe the experimental data, make new predictions, and help guide future experiments in the right direction.

This type of give and take relationship is common in any line of research that can be described by equations from the laws of physics to the intricacies of Wall Street. Hell, Russell Crowe even tried to mathematically model the movements of birds in A Beautiful Mind.

One of the problems with theoretical research, however, is that it is theoretical. You can come up with a set of equations that fit the data and make predictions, but seldom do you have all the information needed to create the correct set of equations. Science is a long process and it takes a while to get to the final answers.

Another example; back in 1687, a fellow by the name of Isaac Newton came up with these nifty equations for motion and gravity that perfectly fit the data. Everyone accepted the system of equations as the end-all be-all solution. That is, until another fellow by the name of Albert Einstein came up with a little something called relativity.

Anyways, where I’m going with this is evolution. There are many ways to mathematically model evolutionary systems to mimic how traits are spread through a population, how often mutations will be beneficial and many other phenomena. But one model has always given scientists a bit of trouble. According to the most popular models, the more complex an organism is, the more difficult it should be for genetic mutations to be beneficial and spread through a population. This is often referred to as the “cost” of complexity, and theoretically it is too high for higher animals to evolve.

Take a hammer versus a microscope. If you change the length of something on the hammer by an inch, it probably won’t hurt the hammer’s function much. The same isn’t quite true of a microscope.

However, a new study from the University of Michigan has lowered the evolutionary costs of complex life.

Jianzhi “George” Zhang and colleagues focused on pleiotropy, a genetic phenomenon in which a single gene affects multiple traits. Mathematical models do exist that attempt to encompass the phenomenon, however they are highly theoretical with very little physical, real-world experimental data to inform them. So the group of scientists set out to get some hard data.

The team took yeast, roundworms and mice – organisms with genomes that are well understood – and studied the effects of introducing single mutations to tens or hundreds of different genes per animal.   The results showed that some of the basic assumptions used in the pleiotropy models are fundamentally incorrect.

For example, it has long been assumed for simplicity’s sake that every gene affects multiple traits. However, Zhang’s group discovered that most genes only affect a small number of traits, and those that do affect many traits have a stronger influence. Also, the researchers discovered that genes are grouped together, and that these groups affect only certain groups of traits, but nothing outside of those specific groups.

When these results are taken into account and the evolutionary equations are remodeled to reflect the data, a new result emerges. It turns out that complex life forms actually are able to adapt more easily than the simplest organisms as well as the most complex ones. Because the theories now predict that complex life forms should not be hindered by evolution, another argument often used by creationists has been eliminated.

And now I must get on my soap box for a moment.

Evolution is a scientific fact. Go into any laboratory in this country and you can witness simple organisms evolving to adapt to their environment almost in real-time. Do you think bacteria resistant to medications just magically appeared out of the ground? No, their predecessors have built up a tolerance to antibacterial drugs.

Now, if you want to argue that the theory of all life – including humans – evolving from a common ancestor is not true, I will allow the debate, even though it is one of the most thoroughly tested theories in the world and we have yet to find a shred of evidence that disproves it.

But for the love of God, stop telling our children that evolution in general is a sham.

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About bigkingken

A science writer dedicated to proving that the Big Ten - or the Committee on Institutional Cooperation, if you will - is more than athletics.
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