In
footnotes 26-27, Greulich stresses the importance of individual genes
interacting with their environments to create a complex developmental
process. The study of the comparison of
heights of Japanese children in America and Japan suggests that
physical growth and development is largely based on extra-cellular
signals and by environmental influences. All organisms must regulate
which genes are expressed at a given time and regulation of gene
expression is essential for cell specialization in multicellular
organisms. Explain how the environment interacts with gene regulation
to produce specific effects such as Japanese-American children
growing taller than native Japanese children, how height was greatest
in the Middle Ages because of warmer climate, and how twins can have
differences based on their interaction between genes and environment?
How does this relate to the core biology theme of interdependence in nature? Use
the Campbell book sections 18.2 and 18.3 and, also, knowledge of
protein and DNA characteristics should be included when describing regulation of genes.
Neil Edat (neil.edat@gmail.com)
Neil Edat (neil.edat@gmail.com)
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ReplyDeleteGene regulation is the potential result of a variety of environmental influences. In the case of height in the Middle Ages, the warmer climate between 900 to 1300 extended the growing season by "three to four weeks" and allowed the "cultivation of previously unavailable land at higher elevations" (http://researchnews.osu.edu/archive/medimen.htm). This enabled a dramatic increase in the availability of food and nutrients which are crucial to growth and development. In addition, the absence of large cities promoted health and growth as disease is not as easily spread across sparsely populated lands. Also, understanding that specific hormones have the ability to regulate gene expression by actively inhibiting the transcription of DNA by causing tighter wrapping around histones making genes less accessible and thereby likely stunt growth and development, the economic and overall security provided by the bounty of the lengthened growing season places less stress on the body's systems therefore producing less transcription inhibiting hormones.
ReplyDeleteIn the case of the American-born Japanese children versus the native born Japanese children, prenatal conditions are key. The mothers in each scenario will consume diets greatly varied in nutritional value due to the conditions under which the food was cultivated and/or processed, also the air and water supply are involved in either stimulating or inhibiting the potential of the fetal growth process. Greater access to a diet rich in iron, magnesium, and vitamin C and less concentrated air pollution leads to the greater height of the American-born child. The higher quality of food contributes as well to the production of ATP which drives efficient metabolic processes for the development of the child.
In relation to the theme of interdependence in nature, gene activation and regulation are reliant on environmental stimuli, however, exposure to these stimuli is not always under an individual's control so they are therefore not dependent on the individual yet still impact them.
Kate White (kw2020@gmail.com)
Gene regulation is hugely affected by the environment, such as the turning on and off of genes. Japanese Americans’ height in comparison to Japanese heights is an example of gene regulation done by the environment. Part of the reason why Japanese Americans are taller is because of the better nutrition available to kids in the U.S. than in Japan. During the regulation of genes, nutrients and energy are very important because many messengers and products involved in gene regulation such as proteins come from what we eat and translation and transcription need nutrients and energy in order to occur. The Japanese kids in the U.S. received more nutrients, therefore, more energy such as glucose was absorbed by the small intestine’s microvilli into the blood stream, and the heart was able to pump more energy rich blood into arteries to be delivered in the capillaries of the body cells. Because the body cells received more oxygen and nutrients, they are able to divide more quickly and so the genes allowed the kids to grow. Kids in Japan on the other hand were not given enough nutrition so their height is not as high as the Japanese kids in America. They don’t receive enough nutrients such as proteins and carbohydrates and form or obtain enough fatty acids, amino acids, nor nucleotides to grow taller because of the lack of macromolecules. So this proves that environment plays a huge role in the growth of height as well. This is an example of epigenetics. Campbell states it is the “Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence is called epigenetic inheritance” (Campbell 358). So in this case, what affected the difference of traits was more of the environment. The middle ages demonstrate the environment’s affect on the traits of a person as well. The people in the middle ages were able to grow taller because the warm environments provided more suitable environment for growing crops. So because of the “stable food supply, people were able to live with reasonable amount of food and because of the nutrients,” people grew taller and were more immune to diseases since the body was able to use more energy to focus on the body defense system, the white blood cells. (http://www.livestrong.com/article/542877-the-average-height-of-humans-over-time/ ) Twin studies are also examples that display the interdependence of humans on nature. Identical twins have the same DNA, so their height should be exactly the same if DNA is what determined height. But, twins that are raised apart in different environments have the possibility of reaching different heights. Campbell states that “no two people will have to same immunity due to different pathogens exposed to the body” This is the same with height, no two people will have the same height due to different environments they are raised in. For an example, if one twin was raised in a poor family while the other in a rich, wealthy family, it is most likely that the twin raised in the wealthy family would be taller because of the availability of food and the body receiving nutrients and building macromolecules. All three of these examples show that genes are constantly interacting with the environment and traits can be altered thanks to the environment. Shenk stated that our genes are like “volume knobs and switches. Think of a giant control board inside every cell of your body” (19). The switchboard inside our body is constantly regulated to control how the genes will be expressed and how much of that gene will be expressed thanks to the interaction between our body and our environment.
ReplyDeleteBing Zhao (bingzhao9@yahoo.com)