utenzi

I read an article in Seed , a science publication positioned between the serious research journal and the wide circulation science magazines, the other day that sparked my interest. The article focused on the role of hedgehog, a gene I mentioned in a post the other week , in how the Mexican blind cavefish--pictured over there to the left--lost its eyes over time. The article, written by Pz Myers , explores various biological explanations for why a species would lose functionality, such as flightless birds or eyeless fish. The species he focuses on is the Mexican blind cavefish which dwells in underground rivers where they are never exposed to light. The first explanation, economical adaptation , is the one I learned in college, long before DNA analysis was available. This type of adaptation says that it requires a finite amount of time, energy, and effort to build an eye so that over time, if the eye doesn't contribute to the welfare of the species, the eye will cease to be made. T...

There's an interesting article on Sonic Hedgehog in the January 18 issue of Nature . I'm used to seeing this gene mentioned when discussing mammalian function or development but not fish--although the article refers to cartilaginous fish only. While both humans and cartilaginous fish are vertebrates we diverged so long ago from the chondricthylans that it's easy to forget that we still share quite a few genes. One of those genes is Shh, commonly referred to as Sonic Hedgehog , pictured over there to the left. Shh, in mammals, encodes a signaling molecule that plays a central role in developmental patterning, especially of the nervous system and the skeletal system. It's highly conserved and mutations in the gene result in serious maladies such as holoprosencephaly type 3. I'm familiar with Sonic Hedgehog due to its being implicated in causing tumors and thus of interest to cancer investigators. Getting back to the article in Nature, it demonstrates how Shh is conse...