What we can observe via Pseudogenes?

Pseudogenes are dysfunctional relatives of known genes that have lost their protein-coding ability or are otherwise no longer expressed in the cell(Pseudogenes). In other word, pseudogenes is the genes contains same/similar exons but lack of introns of functional genes. A genes become pseudogenes once the enough mutation accumulated. 


What the importances of pseudogenes? After I read article from scientific american ( sci-am), in summary this articles explain about on the human evolution. Human accumulates pseudogenes so that reducing the ability of smell and grew more for vision. Different people has different pseudogenes, That why is explain the different perception of odour for different people like "You smell flower, I smell stale urine". Each of us live on our olfactory world. “Everybody’s olfactory world is a unique, private world,” says Andreas Keller, a geneticist at the Rockefeller University.


Genetic variability contribute to different behavioral variability.   When  Keller and his colleagues asked 500 people to rate a panel of 66 odors for intensity and pleasantness, they gave the full range of responses—from weak to intense and from pleasant to unpleasant. In an ongoing study at the University of Dresden, Thomas Hummel and his associates have tested 1,500 young adults on a panel of 20 odors and found specific insensitivities to all but one—citralva, which has a citrus smell. Based on these findings, Keller suspects that each person has an olfactory blind spot.


These studies have wider implications than smell, said geneticist Doron Lancet of Israel’s Weizmann Institute of Science. Because several genes contribute to the detection of most odors, understanding the genetics of olfaction and the way mutations spread in a population is yielding insights into the mechanisms of poly­genic diseases such as coronary heart disease and diabetes.

Besides that, is that Pseudogenes also contribute in development of one species? Compare the tiger and the house cat. The house cat like the miniature sizes of tiger. On the evolution pathways, may be pseudogenes can explain the how the tiger evolved to cat in term of developmental genetic.


Just take a look the Purring mechanism. ( Purr).  The cat from Felis genus is the only cat can purr. On other big cat species, felids of the Panthera genus (Tiger, Lion, Jaguar and Leopard) also can purr. The subdivision of the Felidae also can "purr" or can more suitable word is roaring. The roaring cat differ with the purr cat based on hyoid anatomy. The ‘roaring cats’ (lion, Panthera leo; tiger, P. tigris; jaguar, P. onca; leopard, P. pardus) have an incompletely ossified hyoid, which according to this theory, enables them to roar but not to purr. 

However  the snow leopard (Uncia uncia, or P. uncia), as the fifth felid species with an incompletely ossified hyoid, purrs (Hemmer, 1972). All remaining species of the family Felidae (‘purring cats’) have a completely ossified hyoid which enables them to purr but not to roar. However, Weissengruber et al. (2002) argued that the ability of a cat species to purr is not affected by the anatomy of its hyoid, i.e. whether it is fully ossified or has a ligamentous epihyoid, and that, based on a technical acoustic definition of roaring, the presence of this vocalization type depends on specific characteristics of the vocal folds and an elongated vocal tract, the latter rendered possible by an incompletely ossified hyoid.


If we observe the pseudogenes in cat and related with tiger we can understand more about the evolution of cat in purring mechanism, on the other hand better understanding of developmental genetic.