Genetic switch for limbs and digits found in primitive fish: Before animals first walked on land, fish carried gene program for limbs
So much cool:
The research team compared a genetic switch region called CsB, known to regulate limb development in humans, with similar regions in mice, chickens, frogs, and two fish species…  Schneider and colleagues compared the CsB regions from all five species and found that certain sequences were shared between the fish species and the tetrapods. The conservation allowed the researchers to try swapping switch sequences between species to see if they could still drive gene expression in the fin or limb. Remarkably, mouse CsB could turn on gene expression at the outer edge of the developing fin region of zebrafish, and both skate and zebrafish CsB were capable of activating gene expression in the wrist and proximal digits of the mouse limb…  “These sequences function in these organisms despite 400 million years of separation,” Schneider said…  “These new results are actually in line with both the fossil data and the expression data,” Schneider said. “So now we can tell a story where the fossils and gene expression make sense in light of the genetic regulation”…  “There is a whole universe of questions that are opened up by this discovery,” Shubin said…

Genetic switch for limbs and digits found in primitive fish: Before animals first walked on land, fish carried gene program for limbs

So much cool:

The research team compared a genetic switch region called CsB, known to regulate limb development in humans, with similar regions in mice, chickens, frogs, and two fish species…

Schneider and colleagues compared the CsB regions from all five species and found that certain sequences were shared between the fish species and the tetrapods. The conservation allowed the researchers to try swapping switch sequences between species to see if they could still drive gene expression in the fin or limb. Remarkably, mouse CsB could turn on gene expression at the outer edge of the developing fin region of zebrafish, and both skate and zebrafish CsB were capable of activating gene expression in the wrist and proximal digits of the mouse limb…

“These sequences function in these organisms despite 400 million years of separation,” Schneider said…

“These new results are actually in line with both the fossil data and the expression data,” Schneider said. “So now we can tell a story where the fossils and gene expression make sense in light of the genetic regulation”…

“There is a whole universe of questions that are opened up by this discovery,” Shubin said…