DNA and the genetic code
- DNA is a chemical structure that stores biological information. It is the basic block of life and forms the genetic code.
- The genetic code of an individual contains all the information necessary for an organism to live, function and reproduce.
- Each species have their own genetic code, although there is always some variation and many species share parts of their genetic code with other species.
- Because the genetic code is heritable, individuals of the next generation will have code coming from the previous generation... and so on.
- This heritability means that specific traits can be prominent in one region and rare in another region. For example, blue eyes in humans are more common in northern areas and rarer the more we go towards the equator.
The genetic code is flexible
- The genetic code may give different instructions for a specific trait depending on other factors.
- For example, in the European pond turtle the gender of an individual depends on the temperature at which eggs have been brood: under 25 degrees the broods are all-males, and over 30 degrees the brood are all females
- The expression of many traits depend on the environment. This is why even true-twins do not look perfectly alike.
