Origin of species: Protein imbalances doom hybrids

Why do crosses between closely related species fail to produce fertile hybrids? A new study shows that differences in the levels - not necessarily the sequences - of certain key proteins are crucial in mediating reproductive isolation. Two individuals are defined as belonging to the same biological species, if matings between them give rise to viable and fertile offspring. Crosses between closely related, but already distinct, species produce hybrid offspring that are either inviable or sterile, and thus cannot give rise to a self-propagating hybrid lineage.

Read the whole article on Science Daily

More from Science Daily