It has been shown that most sequences of the human genome originated long before humans themselves. Consequently, scientists will use the genome sequences of the 11 non-mammalian animals to learn more about how, when and why the human genome came to be composed of certain DNA sequences, as well as to gain new insights into organization of genomes. In addition, many of the organisms can shed light on human disease.
For instance, the skate (related to many species of shark and cartilaginous fish) was chosen because it belongs to the first group of primitive vertebrates that developed jaws, an important step in vertebrate evolution. Other innovations in this group of animals include an adaptive immune system similar to that of humans, a closed and pressurized circulatory system, and myelination of the nervous system. Understanding these systems of the skate at a genetic level will help scientists identify the minimum set of genes that create a nervous system or develop a jaw, possibly illustrating how these systems have evolved in humans, and how they sometimes go wrong.
Aplysia (Aplysia californica) is a sea slug that has been a very useful model in studying learning and memory in humans. Aplysia have very large neurons which can be manipulated and studied easily by researchers. In 2000, Eric Kandel, M.D., of Columbia University in New York, shared the Nobel Prize in Physiology or Medicine for his work elucidating how memories are formed in the human brain using Aplysia as a model.
The disease-carrying insect, Rhodnius prolixus, spreads Chagas' disease, caused by the par
Source:NIH/National Human Genome Research Institute