Enviromental+Influences

Natasha, Kayla, and Lexy =Enviromental Influences = We live in an changing enviroment. Everyday the enviroment changes, and everyday we change as well. The way some genes are expressed is determined by how the enviroment interacts and helps the genes become noticable. External factors such as light, chemicals, or temperature can affect us even in the simplest ways. Internal factors such as hormones, metablism, and your gender are important to who you are and how your genes will be expressed. The light can change your hair color, Ph levels can change flower color, and change in your diet can change how your genes react and work together in a heartbeat. These are just a few simple things that are change by enviromental influences.

** Temperature and Light **
External environmental factors, such as light or temperature, may affect how genes are expressed in certain organisms. An example of how temperature can be an external environmental influence is a Himalayan rabbit. Himalayan rabbits have the C gene. The C gene is needed for the development of different pigments in the fur, skin, and eyes in these rabbits, and these pigments are differently expressed by the difference in temperature. When the fur colors of these rabbits are white, that means there were no pigments produced because in the warm, central parts of the body this C gene is inactive. When the C gene produces pigments however, this is usually in parts of the body where the temperature is much lower than 35 degrees Celsius, and then cause these areas to turn black.

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Gender is a genetic trait, but in some species this may not be the case. Factors like temperature, oxygen levels, and diet can express the animal’s phenotypes. Even if two organisms have the same genetic makeup, their environment can affect the genes that are expressed. In some reptiles it has been found that the gender of the offspring is determined by the temperature that the eggs are in during development. How do the reptile’s eggs know what the temperature is, or when to change gender? There is a period of time called thermosensitive period, in which the gonadal tissue is able to know the respond to the temperature. =====

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In 1917, a biologist named Thomas Hunt Morgan conducted studies testing how light can influence gene expression also. In his studies he took the same kind of caterpillars and placed them under red, green, or blue lights while others were kept in the dark with no light. Their wings showed dramatic differences when they turned into beautiful butterflies. The butterflies under the red lights had more colorful, bright wings, the green light butterflies had more dusky wings, and the blue light and darkness butterflies had paler wings. The butterflies placed under the blue light and in the dark turned out to be larger than the butterflies placed under the red and green lights. This just shows that there is a very complex interaction between our environment and our genes that defines or determines our phenotype and who we are. =====

Chemicals and Drugs
Chemicals and drugs are very harmful when it comes to affecting genes. The food you eat, and the pollution in the air are all chemicals that could ruin your genes, and even your children's genes. A pregnant lady drinking is an exaple of internal and external influences. Her taking in the drug will cause harm to her and her child, the child could be born with brain defects, and other disablities. The external influence is the pressure for her to keep drinking even if she is pregnant. Cyclops fish are a common occurance in poluted waters. When the fish lay eggs and the wrong chemicals get into the eggs, some fish are born with two eyes, while others are only born with one. In the 1940's many had a problem with blindness because they gave supplimental oxygen to premature babies. When the oxygen levels got to low, it caused brain damage and the trait the child had gotten from their parents was damaged as well, so the children were all blind within the first few days of being born.

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Internal enviroment of males and females are different because of hormones and structural differences. Baldness in males is hereditary, and you get the gene from your mother's X chromosome. Since men only have one X chromosome they have nothing to mask the recessive trait that would normally be hiden. It's hard for people to understand this, becaus it seems that many men in the generations have the problem of balding, but genetics can expain it. Like we said before you get the gene for baldness on your mother's X chromosome. This means that it will be hidden if only one of the dominate genes is present, Since females have two X chromosomes, baldness will not occure unless both chromosomes have the recessive gene that causes baldness.======

Animals
In animals the males are often the ones with the most prominent features. For example horn and antler sizes are bigger in goats and deer, and feathers and scales are brighter in male birds and fish. This is sometimes helpful to attract females, but on the downside can also attract predators. Since the genetic makeup is almost similiar in both males and females how come males seem to have the pretty makeup? Traits that are more in one sex that the other, but are not in the actual reproductive organs are called secondary sexual characteristics.One of the answers to this question is because males can make certain proteins than females, these proteins can often aid in their features. The making of this protein is ancient and has evolved over the years. [|Secondary Sex Characteristics Link] ﻿This link tells a little it more about how secondary sex characteristics work and how it affected evolution. --Kelsie

[[image:http://t3.gstatic.com/images?q=tbn:ANd9GcTF1E7PgAY27fkNmlyeqIYZ7vwpnM7ORMDWuly0hLRxhyZyx6jLig&t=1 width="268" height="188"]]
We hope you now understand that genetics arent the only thing that can determine the outcome of a trait. Many things such as temperature and light can affect a human, or an animal. Next time you see a diffrence in twins, you will realize if they were raised in two diffrent enviroments that their traits will show diffrently. There is also internal things that change you as you age. I hope our page informed and educated you on thes influences.

For interactive games on genetics you could visit the site: []

Play the game on picking out male and fremale goats based on horn size and body shape [] Sites 

[] --(Pear) This website tells the male and female pattern hair loss, it's the gene driven but not your gene fate! :) [|http://www.ncbi.nlm.nih.gov/pubmed/6765314](milk) Environmental influences on postpartum reproduction of the ewe, cow and sow are quite evident. [] (Neay)Genetic and Environmental Influences on Transitions in Drug Use

Works Cited

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Ralston, Amy. __Environment Controls Gene Expression: Sex Determination and the Onset of Genetic Disorders.__ 2008. 2011 . =====