Expert: Dana Krempels, Ph.D. - 2/5/2008

Question
A friend and I are currently disputing evolution and his main point is that Rh- blood only occurs in certain humans but is non-existant in any primates. He says that it is not a mutation and the blood origin proves that Evolution is a flawed science. Is there any evidence that proves otherwise?

Answer
Dear Katrina,

The Rh factor that gives human blood types one of its main immunological characteristics is a specific type of protein inserted into the plasma membrane of red blood cells.  In Rh+ persons, the protein is present.  In Rh- persons, the protein is absent.

The red blood cells (and all cells, for that matter) have *numerous* proteins inserted into their plasma membranes, including those that code for ABo blood types, act as portals for various molecules and hormones, and generally serve a wide variety of functions.

Your friend is mistaken about nonhuman primates lacking an Rh factor.  They have a version of this protein that is unique to each species, and the very reason that the proteins are different across species is because the DNA encoding them has undergone mutation over time.

In any case, his argument that a single protein found in one species but not another shows his ignorance about evolution and how it proceeds.  Evolution is not a flawed science because it's not a science.  It's also not a theory.  Evolution is an *observable phenomenon* that's going on right now.

If your friend believes that bacterial populations can genetically change over time in response to exposure to antibiotics (and they can; there's no argument about that), then he believes in evolution.  Same thing for insects and weeds becoming resistant to pesticides and herbicides.  Evolution is merely change in natural populations over time, and we can see that happening *everywhere*.  

The only thing theoretical about evolution is *how it proceeds*, not that it happens.  Not believing that evolution occurs is a bit like believing that the earth doesn't revolve around the sun.  You don't *have* to believe it, if you'd prefer to think that the big glowing ball in the sky is Magic Dragon to Keep Us Warm.  But it's really kind of silly, right?  I prefer to accept what I can see with my own eyes.

Hope that helps.

Dana