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Section 12-2 Polygenic Traits

Section 12-2 Polygenic Traits. What is a Polygenic Trait?. A polygenic trait is one that is controlled by many genes found on different chromosomes . Traits that show a range of phenotypes fit this pattern.

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Section 12-2 Polygenic Traits

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  1. Section 12-2 Polygenic Traits

  2. What is a Polygenic Trait? A polygenic trait is one that is controlled by many genes found on different chromosomes. Traits that show a range of phenotypes fit this pattern. The majority of physical, behavioral and metabolic traits are controlled this way.

  3. What is a Polygenic Trait? Think about making a decision to go to a party as a parallel. There are a few main questions that to be answered before you can go. Are you invited? Do you want to go? Do your parents approve? Then there are less important questions that still impact your decision. Do you have a ride? Do you need a date? Does it fit your schedule? Do you need to wear or bring something specific?

  4. Animal Polygenic Traits

  5. Human Height Height is one of the most complicated polygenic traits. It is influenced by hormones that cause differences in men and women. It is controlled by over 90 gene pairs! Some genes follow the complete dominancepatterns while other follow more complicated inheritance modes that are additive.

  6. Human Skin Color Skin Pigmentation is another polygenic trait that is controlled by at least 3 main genes that are expressed equally. Various combinations result in different density of melanin and shade. Regulatory genes usually result in darker pigmentation vs. lighter.

  7. Human Skin Color There is one overriding gene for pigment deposition. If it is not expressed an albino results regardless of the other genes. All ethnicities can exhibit this trait!

  8. Human Eye Color Eye color is controlled by at least six genes that are expressed in a hierarchy. Two main genes control expression first. One gene codes for pigment in the back of the iris to give color vs. none. Another gene has the dominant form that codes for a lot of pigment in the front to give brown eyes.

  9. Human Eye Color If this gene is recessive it codes for some or no melanin in the front of the iris that results in light eyes. Some melanin in frontresults in green or hazel eyes. No melanin in front results in blue or gray eyes.

  10. Human Eye Color The main genes code for melanin and color. Modifier genes are expressed to give differences in shade and pattern.

  11. Polygenic Disease Inheritance Polygenic diseases involve an interaction of factors. Epigenetics looks at how the DNA can be affected to cause genes to be expressed differently.

  12. Polygenic Disease Inheritance When it comes to treating polygenic diseases, a more individualized approach is needed. Pharmacogentics is a new branch of science dedicated to the development of drugs based on different gene forms that are involved in disease transmission. Individual DNA profiles will make it possible to personalize medicine in the near future.

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