Embryos and Evolution
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All animals start as single fertilized cell that rapidly divide and begin to form specialized tissues, organs, and organ systems until you have an organism. The specialization and development of tissues and organs are the result of specific genes being turned "on" and "off ."
In The Origin of Species, Charles Darwin's groundbreaking book on evolution, he wrote "whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved." Evolution has been impacting our planet's organisms since the beginning of life, yet our own understanding of evolution is still very new and there is still much more to understand. The understanding and research in evolution has been moving at a rapid pace following Darwin's groundbreaking publication.
In the early 20th century scientists no longer relied simply on physical characteristics to understand how heredity worked, because they were able to understand heredity through the understanding of genetics and genes. This new understanding of genetics allowed scientists to move forward in their understanding of evolutionary biology through a synthesis of new genetic research and Darwin's original tenets; Natural Selection, Heredity, and Variation.
Later in the 20th century the field of embryology merged with genetics and evolution. This merger has allowed scientists to understand evolution in even greater depth by explaining that there is a commonality between all life forms in respect to their genes and development. This commonality of the genetic instructions can be seen through the expression of physical traits seen in embryos as they develop from single cells to complex life forms.
Why This Science Matters
Some research indicates that many sharks do not develop cancer, yet the human species does. This cancer resistance may be the result of a gene. So is there a way that scientists can turn on the genes in humans that are equivalent to those that give sharks cancer resistance? Comparative embryology and genetics may allow scientist to one day turn the cancer resistance genes on with the result of ending cancer as we know it. Through embryology a greater understanding of how genes themselves have evolved and will continue to evolve in different species, can lead to a greater understanding of genetic mutations and the causes of certain diseases. Understanding how these genes are turned "on" or "off" in different organisms may allow scientists to develop the mechanisms to turn mutated or harmful genes off.
Developmental biology research may also allow scientists to see how genes are expressed in organisms of similar families as they develop and grow. Understanding how specific genes are expressed in developing organisms allow scientists to better understand how stems cells can develop into various types of tissues. The mechanisms that turn genes “on” or “off” in certain stages of development or in specific regions of the body may allow scientists to one day turn specific genes in stem cells on to create specific tissues in specific regions of the body.