Biological species are often defined on the basis of reproductive isolation. Ever since Darwin pointed out his difficulty in explaining why crosses between two species often yield sterile or inviable progeny (for instance, mules emerging from a cross between a horse and a donkey), biologists have struggled with this question. New research into this field by basic scientists at Fred Hutchinson Cancer Research Center, published online Oct. 22 in Science Express, suggests that the solution to this problem lies within the “dark matter of the genome”: heterochromatin, a tightly packed, gene-poor compartment of DNA found within the genomes of all nucleated cells.
Naturally I read my feeds in reverse time order. So this was posted at 11:23 AM while my previous post was up at Eureka Science at 6.28 PM. While the previous work only describes in generalities the regions in the chromosomes responsible for reproductive isolation, this paper not only gives more specific information on the regions but identifies some of the proteins involved.
At a quick glance, I would say that this paper may have more impact in the long run, as it provides an actual mechanism with the possible culprit for rapid creation of new species.
Time will tell.