Evolution, Past and Present

Two related articles showed up in my news feed today, both having to do with evolutionary mechanisms. We’re still a long way from Jurassic Park, but at the least, these studies give us a window into what evolution’s capable of doing and how it works.

The first concerns an experiment conducted by Georgia Tech scientists, who spliced a 500 million year old bacteria’s Elongation Factor-Tu gene into the genomes of the modern day E. coli. Neither the article nor the press release are clear on what exactly EF-Tu does, so I had to dig around the internet and resurrect some of my lapsed biology knowledge to understand its role.

Genes are synthesized into amino acids; these in turn are combined into peptide chains, which fold in complex ways to form proteins like hemoglobin. The first step of gene-protein synthesis is mRNA transcription, which is a blueprint of sorts for the proteins to form. When the mRNA exits the nucleus of a cell, it’s bonded to a ribosome, itself a large protein. While the ribosome “reads” the mRNA, transfer-RNA or tRNA molecules holding amino acids corresponding to the bases in mRNA are linked into one large chain. From what I can understand, EF-Tu makes sure that the correlation between amino acid and groups of bases (the codons) are correct; if they are, then EF-Tu allows the amino acid to be added to the chain and facilitates peptide elongation (aha! And here you just thought it was a name).

The long and short of it is that EF-Tu is crucial to the protein creation process and, therefore, to life itself. When initially placed inside modern bacteria, EF-Tu’s performance wasn’t impressive. But over time, the bacteria with EF-Tu spliced in seemed to perform just as well as, if not better than, their modern day counterparts. It wasn’t the EF-Tu gene itself that mutated, however; instead, the proteins interacting with the EF-Tu mutated to accommodate the ancient gene.

This research is interesting, certainly, but I’m even more interested in why the gene itself didn’t evolve. It might be harder for a genetic sequence to accumulate mutations, and easier for the transcription process to interject mutations in the associated proteins. Then again, neither the press release nor the article gives much information about which proteins evolved and why this might be the case.

The second article, focusing similarly on evolution, is a little more straightforward: a group of researchers from the Wilfrid Laurier University in Canada have bred fruit flies that have evolved to be able to count. It’s rather an elegant experiment, where flies were tested to see if they were prepared for a stimulus after a specific number of times.

What, I wonder, would’ve happened if the number of times the light flashed was replaced by a sequence of letters? I’m not saying flies would be able to learn language, but perhaps they’d be able to distinguish symbols. Would that be a legitimate point for the argument that pictorial and symbolic representations are also inherent traits?

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