[Jack Garcia]

I recently learnt that on Madeira there have been instances of mice (Mus musculus, the same species as our mice) undergoing chromosomal shifts (fusion) and subsequent speciation within the 500 years since they've lived there. Apparently there are up to five or six species which have arisen out of one. In that short of a period of time, for any mammal to have become another species even once is remarkable I think, so five or six is awesome to think about.

The main article is viewable, as far as I know, only with subscription, but here are some other articles that discuss what has been discovered:

http://evolutionlist.blogspot.com/2006/ ... m-one.html
http://www.genomenewsnetwork.org/articl ... mice.shtml
http://users.rcn.com/jkimball.ma.ultran ... ml#Madeira

I find this fascinating, and I want some of these newly-arisen species!

What are your thoughts? Do you think that in the 120 years since Maxey there's any chance a chromosomal fusion has occured in any one line of mice and been reproduced in that line, rendering them their own species? Of course we'd never know, but if there's a line out there that breeds well with itself but not with outcrosses I think it's possible! I have a line of mice that has only sucessfully outcrossed once, ever, although they breed fine with each other. Interestingly, the F1 generation were all sterile (then again, there were only 3 of them to begin with)!

 

[bethmccallister]

This is incredible! I have always been facinated by Darwin's theory of evolution with the Galapagos Islands which show that species can progogate and survive through natural selection. The islands being isolated allowed through chance, different climates and natural forces such as the type of food and availability thirteen different types of finches to evolve.

It sounds like the Madeira Mice have 6 new species determined by their chromosomes and you can't really see a difference unless you look at the genecodes...way cool...I hope to continue following the story...thanks for sharing!

 

[Jack Garcia]

You're very welcome!

Evolution through natural selection is fascinating, isn't it? It's amazing to me that it can happen so quickly in species as complex as mice or other mammals.

 

[SiamMeece]

Thanks for posting, so interesting! Speciation by changes in genotype, not phenotype. So unlike the African cychlids that differ in phenotype and behaviour enormously but in genotype very little. Two different sides of evolution.