Vertebrates' transition to living on land, instead of only in water, represented a major event in the history of life. Now, researchers reporting in the December issue of the Cell Press journal Developmental Cell provide new evidence that the development of hands and feet occurred through the gain of new DNA elements that activate particular genes.
"First, and foremost, this finding helps us to understand the power that the modification of gene expression has on shaping our bodies," says Dr. José Luis Gómez-Skarmeta of the CSIC-Universidad Pablo de Olavide-Junta de Andalucía, in Seville, Spain. "Second, many genetic diseases are associated with a 'misshaping' of our organs during development. In the case of genes involved in limb formation, their abnormal function is associated with diseases such as synpolydactyly and hand-foot-genital syndrome."
In order to understand how fins may have evolved into limbs, researchers led by Dr. Gómez-Skarmeta and his colleague Dr. Fernando Casares at the same institute introduced extra Hoxd13, a gene known to play a role in distinguishing body parts, at the tip of a zebrafish embryo's fin. Surprisingly, this led to the generation of new cartilage tissue and the reduction of fin tissue—changes that strikingly recapitulate key aspects of land-animal limb development. The researchers wondered whether novel Hoxd13 control elements may have increased Hoxd13 gene expression in the past to cause similar effects during limb evolution. They turned to a DNA control element that is known to regulate the activation of Hoxd13 in mouse embryonic limbs and that is absent in fish.
"We found that in the zebrafish, the mouse Hoxd13 control element was capable of driving gene expression in the distal fin rudiment. This result indicates that molecular machinery capable of activating this control element was also present in the last common ancestor of finned and legged animals and is proven by its remnants in zebrafish," says Dr. Casares.
Freitas et al.: "Hoxd13 contribution to the evolution of vertebrate appendages."
Cell Press: http://www.cellpress.com
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
An innate ability some people have to manipulate their vocal frequency could be the key to sounding charismatic, according to new research.
Time-lapse imagery of scavengers tucking in proves that dead jellyfish aren't unpalatable after all, so can return nutrients to the sea's food webs
When bird pairs break up females often lay more eggs with a new partner, but the split can be disastrous for the male of the species
Spontaneous gene mutations, not ones inherited from parents, increase a child's risk of autism, scientists say. By comparing genes within families they've identified more than 100 suspects.
Slovenian archaeologist Ivan prajc is behind discovery of three significant ruins in the remote jungles of the Yucatán peninsula
Every year, Nikon selects the most artful, scientifically enlightening and skillfully produced images from thousands of submissions for its Small World microscope photography contest. Tomorrow, another set of impressive winners will be announced for the contest’s 40th year.
Seaview divers routinely cover 2 kilometers in a dive and generate 3,000 panoramic images in a day. Only a fraction of the best are uploaded to Google Street View.
Meeting sharks can be a moving experience, says photographer Jean-Marie Ghislain, who works to educate people on the plight of sharks around the world
From kraken to mermaids, some monsters are real—if you know how to look for them
Australia's Academy of Science says a government draft plan to protect the Great Barrier Reef will not prevent its decline.