I like worms. Worms do wonders for our soil. My summer garden looks fabulous thanks to our friendly worms.
Now I have even more respect for worms. The Planarian flatworms in particular are now under study as they have the amazing ability to re-grow any missing body part. An exciting development for study of eye diseases in humans and other verterbrates.
A published report includes a lengthy and impressive catalog of genes that are active in the planarian eye as a model system in gene functionality.
The planarian flatworms genetic makeup is new, based on an eye with one optic cup lined with pigment celle. Prior to this study the compound eyes of fruit flies were the most commonly and thoroughly studied. Planarians present a new genetic system, with an eye based on one optic cup lined with pigment cells.
An analysis of more than two thousand planarian eyes helped to create a list of genes that showed enriched activity in the flatworms. A number of the identified genes are reportedly known to have versions that play a role in a vertebrate eye that have not been found in the study of the common fruit fly eye. Among these are genes responsible for full eye development and others that are related to progressive retinal degradation.
One of the main genes identified in the planarian flatworm eye development is the transcription factor ovo, which triggers the expression of many other genes as the eye forms.
Ovo had up to now been associated with germ cell and neural tube development in other organisms, but not with the eye. In the flatworms, ovo is vital for regeneration of the eye and also keeping the maintenance of it in the adult species. It is active in eye development invitro also.
It was reported that when ovo was turned off, planarians with head amputations could not regenerate their eyes and eyes of otherwise normal adult planarians vanished after just a couple of months.
Far more has been learnt about the genes that govern eye formation in these animals and the benefits of studying diverse model species is obvious as the discovery of a critical role for ovo has shown.