This article in the New York Times talks about how dust mites are proof that evolution does not always move forward but can actually regress. A study in the University of Michigan found that  the phylogenetic tree of dust mites shows that dust mites themselves are free-living organisms, and they evolved from parasites, and parasites evolved from free-living organisms. This article stood out to me because it reminded me of our discussion in class that covered how no one organism is the “most advanced,” but rather all organisms have evolved to be best fit to their particular environments. Understanding that concept,  I would suppose that a long time ago free living organisms were no longer a good fit for a certain environment and so after a long period, parasitic organisms evolved by natural selection. Then, in another environment, being a parasitic organism was no longer favorable and being free-living was a better fit, and so natural selection created the free-living dust mite.  Natural selection selects for organisms to fit their environments, there is no goal of creating the ultimate, perfect organism. If becoming a better fit for the environment means the return of a trait of an ancestral organism, the fact that the trait was previously discarded is irrelevant; that trait is now a good fit again.

To tie this in with medicine, the article concludes by saying that discovering the free-living nature of dust mites gives a new genetic insight into these organisms that will help scientists to understand how people with dust allergies react to dust mites, possibly leading to the production of a better allergy medication. If only there could also be some medical advancement in spring allergies too; it’s almost that time of year. Makes you wonder why evolution has not eliminated allergies in general: dust or pollen based.

The article’s link is below:

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