Lack of Genetic Diversity? No Problem for the Island Fox!

The island fox may only weigh a little over two pounds when full-grown, but even this is not the most surprising aspect about these foxes. According to this scientific journal, researchers have discovered that the island foxes are nearly identical, genetically speaking. Robert K. Wayne, a geneticist at the University of California, has been studying the foxes since 1990 trying to understand how these foxes are able to thrive, especially considering one island fox community has a record for the least genetic variation in a sexually reproducing species. After sequencing the genomes from each of the six subspecies, the DNA was found to be virtually identical. There are a number of possibilities as to how these foxes have been thriving for thousands of years, such as being the top predator without exposure to inbred difficulties and the genes being programmed to be switched on and off, called epigenetics.

This fox phenomenon is very intriguing, especially since even the scientists who have been researching this topic for nearly 30 years still do not know exactly why or how these foxes are able to thrive how they are today. Another interesting aspect of this article was the option to interbreed the subspecies in order to increase their genetic diversity. There was a promising instance in which Florida panthers interbred with a Texas subspecies in which the new genes helped the Florida population to grow. However, I would have to agree with Dr. Wayne in which he would not advise this "genetic rescue" unless there was strong scientific evidence that the low genetic variation was significantly hindering the fox's populations.

The original article can be found here.

Low Genetic Diversity in Island Fox

Recently it has been discovered by a group of geneticists at the University of California that one fox species has a surprisingly low genetic diversity. The species looked at are referred to as the island fox and can be found on The Channel Islands. According to studies in the past, these fox share an ancestor with the gray fox that was brought over by Native Americans about 13,000 years ago. Scientists are still unsure of exactly how island fox appeared on the islands. The island foxes are even smaller than a house cat and can weigh only 3.25 pounds.

Normally it is common for species that lack genetic diversity to be at risk for extinction, but this does not seem to be the case with the island fox. Dr. Robert K. Wayne has been studying island foxes since the 1990s, but has had to wait for the technology to sequence their entire genomes. He sequenced the genome of one fox from each of the six subspecies and found little difference in the DNA the foxes inherited. This phenomenon is called genetic flatlining which usually poses a threat to the species survival , except in this case.

Researchers have looked into why the island fox is able to live on and came up with a few theories. The first reason could be that they are one of the top predators on a small island and may have even had the help of humans on the island. Secondly, they may experience epigenetics which can cause genes to switch on and off. This would mean that even if they all have the same genes different ones are expressed. The third possible but unlikely way is if the gene pool had added variation if a different species had come to the islands. Researchers are still unsure of why the island fox did not become extinct years ago.

Although island fox studies may seem insignificant it actually could be helpful in years to come. Studies in this area does not only help to make sure that the island fox continues to reproduce, but also other species. Researchers believe that persistence of small populations goes hand in hand with the concern of low genetic variation.   As more research is done in this area hopefully a solution will be made to prevent extinction of other species.