During the course of the past thirty years, the study of model organisms has become more significant in the study of embryological development. A model organism is a species that is easy to cultivate and monitor in a laboratory environment and is used to represent broad groups of organisms. Examples of successful and important model organisms include the Ascidia, Zebrafish, and Medeka species. Through intense researching of these organisms, scientists have been able to gain valuable insight into the developmental processes of many complex vertebrates, including humans.
Model organisms are used to study embryonic development for several reasons. These organisms have shared characteristics including short life spans and generation intervals, rapid development, and easily distinguished embryos, which make them ideal experimental targets. Through the mapping of developmental processes and similarities between the model organisms and other major vertebrate groups have been discovered, the model organisms serve to represent numerous complex organisms. Also, research involving the model organisms has allowed scientists to gain a better understanding of developmental processes and functions (Anderson and Ingham 1003).
Since 1871, ascidians, or sea squirts, which are simple invertebrate chordates, have been used as model organisms to study embryonic development. The ascidia embryo represents an ideal model for vertebrate development because it has the same basic developmental and morphologic features of vertebrates. Furthermore, as a less complex organism, the ascidians have only a few hundred cells rather than the thousands of cells found in most vertebrates. The ascidia species was also chosen as a model organism because it has a...
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...mportant common genes for eye development (Wittbrodt et al. 2002).
Through the use of model organisms, scientists have been able to understand complex processes of embryonic development much better. By using organisms that are smaller, simpler, and easier to observe in a laboratory situation, scientists have made notable achievements in understanding the origins of tissues, organs, and various systems involved in the growth of vertebrates. Model organisms such as the ascidian, zebrafish, and medaka species have each proven important in scientists' study of vertebrate development. Furthermore, the understanding of these processes and the genes involved will likely have medical applications in the future. With a better understanding of the formation and functioning of organs and systems, scientists could find more effective ways to recognize and treat diseases.
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
...ape formation, movement of cardiac progenitor cells, heart tube, and heart function. A novel development of more specific assays, advance genetic screen efforts will provide new knowledge on cardiac development in the following years. Additionally, because of the zebrafish distinct features and its similarities to vertebrae, the zebrafish might become many researchers preferred model organism to study many mammal organs. Recently, the zebrafish has been used to study mechanisms that cause human cardiac and liver diseases and to model human hereditary and developed cardiac diseases. Due to the increase in sequencing efforts, the developing interest to study human liver and cardiac diseases. Also, the increase of resource and the more availability of the zebrafish model used in clinical and basic researchers involved in studying the liver, as well as cardiac diseases
In the mid 1960's, R. G. Edwards and colleagues at Cambridge University began studying differentiation of rabbit embryonic cells in an artificial environment. They manipulated these embryonic cells into specific types of form such as connective tissue and muscle neurons.
The word “monotreme” is Greek for “one-hole,” referring to the cloaca that is the exit for the urinary, reproductive, and excretory systems (Dawson, 1983). The creatures are oviparous--the females lay eggs that develop outside of her body. This paper will explain the background of the animals, the anatomy of the tract and egg, breeding behavior, and genetics behind this unique reproductive system. It will pay special attention to the similarities of the monotreme reproductive system to those of animals we are more familiar with.
Liubicich, D.M., et al. 2009. Knockdown of Parhyale Ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology. PNAS 106 (33): 13892-13896
The relationship between disability and biomedical model is very complex; to understand the concept one needs to understand the biomedical model and the definition of disability. disability is a term that describes a person’s inability to perform daily activities. Biomedical model states that a disability is caused by a disease, disorder, mental or physical condition that deprives a person of the basic necessity of life. Furthermore, the medical model views a disabled person as functionally limited as it defines the norms for human functioning. From these two definitions, it can be concluded that both disability and the medical model are interlinked in ways of how a person’s inability to function have an impact in the interaction of society.
Matthews, R.A.J. "Medical Progress Depends on Animal Models - Doesn't It?" Journal of the Royal Society of Medicine. 101.2 (2008): 95-98. Print.
Cloning is not new; experiments with frogs and toads go back to the 1970’ with the experiments concerning animal and plant embryos have been preformed for
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
2. Moore, K. L. The Developing Human: Clinically oriented embryology, 4th edition. Philadelphia PA: W.B. Saunders Co., 1988, p.146.
The first neural induction in amphibian embryos has given the Nobel Prize in Medicine award to Hans Spemann in 1935 for his “Spemann-Mangold organizer” paper. The discovery with her student Hilde Mangold leads to establishment of a neuroectodermal primordium from where the nervous system arise involving induction of chemicals such as the fibroblast growth factor (FGF) and WNT signalling, together with inhibition of bone morphogenetic protein-4 (BMP) signalling activity to promotes neuron development. Spemann’s study has successfully identified a morphologically distinct cluster of mesodermal cell located in dorsal lip of blastophore known as ‘organizer’ which has the potential in neural induction. BMP will trigger neural induction and are formed during the gastrulation in vertebrate embryo which is secreted by ventral gastrula signalling centre (Spermann H, Mangold H, 1924). In a normal mechanism BMP binds with receptor on ectoderm cell to form epidermis. However, by inhibiting BMP, ectoderm cells will differentiate to form the neurons cells without the presence of neural inducers t...
Sadler, T. W., and Jan Langman. Langman's Medical Embryology. Philadelphia: Lippincott Williams & Wilkins, 2006. Print.
Fetal development begins with the fertilization of an ovum; the female reproductive cell, capable of developing into a new organism upon fertilization, by a sperm; the male reproductive cell capable of fertilizing an ovum. Three stages follow fertilization: the zygote, the embryo, and the fetus (Whitney & Rolfes, 2016, p. 475).
The process of ectogenesis can be traced back to the first test tube baby or “in vitro fertilization” (IVF). Experiments started by Dr. Helen Hung-Ching Liu, the actual formation of an artificial womb to see if it could be created and still theoretically be life-sustainable. The next experiment was by Dr. Yoshinori Kuwabara, who went as far to
First, cloning has a long history dating back thousands of years, which has allowed the process of cloning to evolve to more complex organisms. Cloning was first experimented with different plant offspring (“Cloning” n.p.). The cloning process of plants in the past was very simple and only required parts of the plant such as roots, stems, and leaves to be cut and planted, which would grow into an exact copy of the initial plant (“Cloning” n.p.). In the 1950s, scientists were able to successfully clone frogs in a more complex manner by transferring the nucleus from a tadpole cell to a frog egg that had already had its nucleus (“Cloning” n.p.). Scientists later discovered that their cloning procedure was a success when the frog that grew from the egg experimented on had the same genetic makeup as the tadpole that donated a nucleus from one of its cells (“Cloning” n.p.). Dolly the sheep is the product of the first successful cloning of a mammal (“Cloning” n.p.). “In 1997 Scottish scientist Ian Wilmut and his colleagues announced the birth of a clone of an adult mammal” (“Cloning” n.p.). Dolly was created from a cell of a breast gland from an adult sheep was put in an embryo and placed inside a sheep able to give birth (“Cloning” n.p.). Dolly was born looking identical to the shee...