Awesome powers of common shrew or weakening powers of current classification?

Spread the love
Thumbnail for version as of 07:56, 16 October 2010
Wikimedia Commons

This New Scientist article (Michael Marshall, 28 April 2011)  on the interbreeding of shrews despite the fact that their chromosomes have been rearranged does not use  the “biological species concept”  (it’s hard to know how to do so under the circumstances). Stuck for a term, Marshall calls the differently arranged groups “races” instead. Anyway,

Searle of Cornell University in Ithaca, New York, and colleagues studied two neighbouring races in Siberia. Despite the shrews’ different chromosome Jeremy arrangements, they manage to interbreed. Their hybrid offspring are less fertile than their parents, however.

That’s because the offspring do not have matching pairs of chromosomes, so it is hard for them to make eggs or sperm that have the full complement of genes. But although their fertility is lower, it isn’t zero: they can still have litters of their own. Somehow they are able to assemble up to nine chromosomes in the centre of a dividing cell, and pull them apart one by one in the right way to make viable sperm and eggs. “I think it’s fairly astonishing that they manage it,” Searle says.

He adds,

Eventually the different races may become separate species. Searle says there are shrews that look just like the common shrew, but do not breed with them – and the only difference is how they arrange their chromosomes.

But are we missing something here? Does anyone remember when the concept of  “species” was  meaningful?

One Reply to “Awesome powers of common shrew or weakening powers of current classification?

  1. 1
    Robert Byers says:

    This is interesting and important. To this yEC creationist the classification of creatures is all wrong.
    There are no mammals, or marsupials, or reptiles, or dinosaurs.
    These shrews are simply the same creature from a post flood adaptation diversity.
    Their genetics has nothing to do with their relatedness.
    Their genes does not tell the tale of their heritage and origins of their segregation.
    Indeed having quite different genetic points is no big deal to them or to its origin.
    Genes are not a reliable trail and so not evidence for evolutionism in its claims.
    For example I am sure marsupials are just modified placentals. So the great difference in genetics is simply a reflection of a minor change of these creatures entering some new area etc.
    Triggers in the body hand in glove change the genetics. Genetics is very quickly flexible.

Leave a Reply