Introduction
Current research demonstrates that over seventy percent of the protein coding genes in humans are related to those found in zebra fish. In addition, about 84 percent of the genes that are commonly linked to human disease have a counterpart in the zebra fish. The research therefore highlights the huge importance of the zebra fish species as a human disease research model organism. The zebra fish is a tiny tropical fish that is commonly found in the tropical rivers of South Asia and India (see graphic at the end of essay). Ostensibly, a zebra fish may appear to be a bizarre comparator to humans. However, the zebra fish are vertebrates just like humans and they therefore share a common ancestor. They are outstandingly biologically similar to humans and they share many similar genes therefore making them an extremely important model for comprehending the way genes work in disease and health. There are also a number of very unique features that have significantly contributed to its human disease research attraction. Its genome has some very inimitable features that are not visible in many other vertebrates (Goldsmith 11).
First of all, its time of generation is relatively short and even more importantly, one spawning session can lead to the production of thousands of offspring. Additionally, the maintenance costs involved in researching zebra fish are lower than those of larger mammals. Their genome sequence has the most repeated content in the entire vertebrate’s species. In fact, this repeat content is almost twice as much as the second ranked species. The zebra fish is a brilliant model system for developmental geneticists and biologists. The zebra fish’s externally developing embryos are very clear therefore allowing their organ systems to be visualized clearly as well as allowing them to be investigated in real time. They also have nervous, digestive and cardiovascular systems that are closely similar to the ones of mammals (others (Bibhas and Sivamani 6).
For the past few years, zebra fish have been fruitfully applied as model organism for the elucidation of human disease etiology.
The human disease zebra fish models have been applied in varied medical research fields including cardiovascular diseases, infectious disease, cancer, kidney disease, blindness, deafness, digestive diseases, muscle disorders, hematopoiesis, and neural disorders amongst others (Bibhas and Sivamani 7). Some of the applications of the zebra fish in human clinical disease research are as shown below.
Cardiac Disease
The zebra fish embryonic heart resembles the human heart very closely approximately after a gestation period of three months. The heart is divided into ventricular and atrial chambers and is also lined by an endocardium. There is also the presence of cardiac valves at the chamber boundaries. Accompanied by the relative visualization ease of the heart, these characteristics indeed make a zebra fish a very attractive cardiac model.
An array of zebra fish mutants has been associated with cardiac development/functioning defects. For instance, in one mutant known as Pandora, there is the absence of the heart valve, while the ventricle is absent in jekyll. Another mutant, heart and soul has a greatly reduced heart size while the santa mutant possesses a heart that is 4 times larger than normal. Miles apart is characterized by the absence of the fused primitive heart tubes. The slow mo is characterized by a bradycardia as well as a heart rate that is significantly lower than that of other fish. Another mutant zebra fish known as grindlock bears a resemblance to the human congenital disorder coarctation of the aorta. Circulation does not reach the tail and this is caused by a defect in the dorsal aorta. These examples indeed underline the usefulness of the zebra fish for gene analysis and disease research. Recent mutagenesis screening has established more than 20 mutants possessing perturbations in cardiac patterning and induction using gene markers. Identification of the causal genetic lesions that are responsible for some of the above mutants will only help to provide more molecular details of these crucial development processes (Bibhas and Sivamani 8).
Kidney Disorder
The zebra fish species has become very popular in the study of renal diseases due to their kidney’s anatomical simplicity. Acute kidney injury, nephronophthisis and polycystic kidney diseases are some of the renal defects that have undergone zebra fish modeling. For instance, studies seem to suggest that cilia play a very key role in polycystic kidney disease etiology. Proper cilia function prevents formation of cysts and this theory has been widely supported by the description of several mutants of the zebra fish being carriers of cilia protein mutations such as LRRCC50 and intraflagella transport proteins (Goldsmith 18). In addition, chemical drugs such as roscovitine ameliorate and rapamycin have been used in some of the zebra fish mutants and have generally suggested that the zebra fish can be utilized to pinpoint some potential therapeutic renal cystitis agents.
Diabetes Mellitus
Glucose metabolism study is a very good illustration of metabolic zebra fish models. There is a great similarity between zebra fish glucose metabolism and the mammalian glucose metabolism. The major protein components of the insulin signaling system in the zebra fish has a structure and functional resemblance to the one in mammals. In addition, the adult zebra fish sensitivity to anti diabetic drug effects is very similar to that of mammals. The zebra fish also share a huge similarity with mammals in regards to the posphoenolpyruvate carboxykinase expression regulation by glucagon (C153H225N43O49S) and insulin. Most researchers in this field seem to suggest that utilizing changes in this enzyme expression could be the marker for the effects of antidiabetic drug studies (Bibhas and Sivamani 8).
Muscular Dystrophy
This disease affects very many people in the world especially those of the male gender. The disease causes progressive degeneration of muscles and can eventually lead to death. The disease results from the mutation of dystrophin (a sarcolemmal protein) that is located in the x-chromosome. An N-Ethyl-N-Nitrosurea (ENU) screening of the zebra fish revealed a mutation referred to as sapje. This mutation was discovered to reside in the zebrafish’s Duchenne muscular dystrophy gene and therefore causes progressive muscular degeneration of the zebra fish larvae. This has paved way for the further study of this defect and its relation to the human race (Goldsmith 16).
Conclusion
In light of the above facts, it is clear that the zebra fish is gaining acceptance rapidly as capable organism model for the study of human diseases. The use of the zebra fish facilitates the success of cost effective studies than can be combined with advanced molecular tools to give a real sound insight into the basics of human diseases. The zebra fish is therefore a very well established or formulated model organism that has made important contributions to the recognition and characterization of the pathways and the genes that are involved in the development, the behavior and the organ function. More importantly, the zebra fish has become a very crucial resource for the identification of genes that are involved in human clinical disease research.
The zebra fish
An anatomy of a zebra fish
Works Cited
Bibhas Kar, Sivamani Subbiah. Zebrafish: An in Vivo Model for the Study of Human Diseases. International Journal of Genetics and Genomics. Vol. 1, No. 1, 2013, pp. 6-11.
P. Goldsmith, “Zebrafish as a pharmacological tool: the how, why and when” Curr. Opin. Pharmacol. Vol. 4, pp. 504-512, 2004.
