Thursday, March 21, 2019

Same Protein, Two Different Fish, Different Ancestor

In an article in The Atlantic, there are some fish that are able to swim in our subzero waters. These fish are able to survive temperatures that would kill other fish. These fish are able to produce their own antifreeze. They have a unique protein in their blood that prevents ice from forming. That protein is a very simple chemical formula which consists of just the same three chemical groups repeating. The two fish that this antifreeze protein is found are called notothens and Arctic cod. These two fish make the same exact protein but these proteins arose from different ancestral genes. The protein found in notothens actually arose from an ancestral gene that makes a digestive enzyme. It turns out that many different species of cod have a very similar gene that can code for this protein. It was determined that the antifreeze protein was actually a mutation of a strand of “junk DNA” which was found to functionless without this mutation. There is also a an article written by Chen, DeVries, and Cheng which discuss how incredible this find is. The way the Atlantic cod and notothens make antifreeze proteins is a great example of how an old protein gene spawned a new gene for an entirely new protein with a new function. It also is an example on how protein evolution, organismal adaption, and environmental conditions can be directly linked.  The two groups of fish had evolved almost identical antifreezes Independently which is an incredible example of convergent evolution. 

1 comment:

  1. Evolution at its finest! it is pretty incredible that these two types of fish have their own type of antifreeze running through there bodies. I wonder how many other wildlife have mechanisms such as this that we don't even know about. pretty incredible to think about.