#2 More on Freaky Mice

Wed, 03 Aug 2011 16:00:33 -0400
active, algerian, breeding, carson, community-news-and-opinion, crossbreeding, european, evolution, findings, freaky, gene, health-wellness-and-safety, house, hybrid, k, mice, mouse, mutation, pesticides, protein, rachel, research, resistance, resistant, rodenticides, silent, site, spring, super, teaching-and-learning, vitamin, vkorc1 [and 1 more]

So, I have indeed posted about these freaky mice in my previous post, hence the #2. There is more than one source of these freaky mice; in fact, these mice can develop resistance to warfarin in two known ways: point mutation, and hybridization between European house mice and Algerian mice. Through spontaneous point mutation through DNA replication, the European house mice could develop resistance to warfarin, but it is more likely that today's European house mice developed resistance through the latter method.

The typical European house mice do not have the gene needed in order to make a protein resistant to warfarin. Warfarin, a pesticides (more specifically a rodenticide), inhibits the action of Vitamin K in mice by attaching to an inhibitory site of the protein (called vkorc1) which attaches to Vitamin K, rendering the mice unable to form blood clots, essentially leading them to bleed to death. However, the Algerian mice, as a result of their grain-only diet in North Africa, have already evolved the gene in order to deal with Vitamin K deficiencies. Other rodents (e.g. certain hamster species) that have grain-only diets also developed this gene.

Sure, as I have stated in my last post, many of the hybrids that formed between the crossbreeding of European house mice and Algerian mice are either infertile or nonviable. However, a very few of the hybrids contained mostly genes from the European house mouse, but have a huge chunk of genes from the Algerian mice related to warfarin resistance. This particular sequence is the vkorc1 gene from Algerian mice. It alters vkorc1 so that it remains functional yet does not bind to warfarin, essentially limiting the toxicity of warfarin on the mouse.

Of course, humans have attempted to use warfarin in order to remove these unwanted pests, but as Rachel Carson states, perhaps it is time to reconsider using pesticides - especially the same ones - repeatedly. Rachel Carson had already noted, in her book Silent Spring, of pesticide-resistant beetles, weevils, moths, and other pests that wreck havoc on agriculture and the environment. This could also apply to pests such as mice, except with warfarin for mice instead of DDT for insects.

Even though warfarin hasn't shown to be toxic to humans (I think), it has proven to be increasingly ineffective in controlling pest mice populations. Through this pressure, the resistant mice survive and multiply, changing the demographics of the mice population, and will prove to be more than a nuisance in households. Perhaps we should seek alternatives, although I do not think cats are effective at removing this menace.

PS: It should be noted that the European house mice and the Algerian mice are separate species, just like how Polar bears and Grizzly bears are separate species (male hybrids between the two are infertile, thus showing the two as separate species). It is reported that the European house mice and the Algerian mice were isolated for around 1.5 million years, meaning they are distantly related - far longer (maybe up to 30x longer) than Neanderthals were isolated from humans. Humans are partially to blame for the introduction of one species onto the other, forming hybrids that could wreck havoc on homes.

More links to the findings in addition to the one under the button:
http://www.mnn.com/earth-matters/animals/stories/freaky-mutant-mouse-steals-genes-to-resist-poison
http://blogs.discovermagazine.com/notrocketscience/2011/07/21/house-mice-picked-up-poison-resistance-gene-by-having-sex-with-related-species/