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== Quick Pre-Lecture on Transposons == | == Quick Pre-Lecture on Transposons == | ||
Look to the image on the right. It is a picture of maize, commonly referred to as corn. Note how there appear to be two types of kernels, speckled and unspeckled. What do you think has caused this? If you guessed that the maize is diseased or rotting you are incorrect. The speckles are caused by transposons, non-coding segments of DNA. Transposons can be viewed as selfish sequences of DNA that are in a constant war with the coding portions of DNA. If the coding portions of DNA did not fight back with transposons, the transposons would copy themselves to make the genome extremely long. Another bad aspect of transposons replicating themselves is that they | Look to the image on the right. It is a picture of maize, commonly referred to as corn. Note how there appear to be two types of kernels, speckled and unspeckled. What do you think has caused this? If you guessed that the maize is diseased or rotting you are incorrect. The speckles are caused by transposons, non-coding segments of DNA. Transposons can be viewed as selfish sequences of DNA that are in a constant war with the coding portions of DNA. If the coding portions of DNA did not fight back with transposons, the transposons would copy themselves to make the genome extremely long. Another bad aspect of transposons replicating themselves is that they sometimes insert themselves in the middle of genes, which causes the genes to often malfunction. Luckily, there is an ancient immune system in place to fight against the transposons. Once a transposon is identified by this ancient immune system the transposon is prevented from duplicating itself. | ||
Going back to the | Going back to the maize example, the kernels without speckles indicates one of two possibilities: the kernel has no transposons, or the kernel has transposons and they have been identified. With the information provided so far you are probably thinking that transposons are pure evil, but they aren't. Transposons have a noticeable role in evolution because they cause significant mutations. I use the word significant because transposons are chunks of DNA moving around and relocating, they dont create small mutations like a T pairing up with a C on accident, they are much larger.<br> | ||
Latest revision as of 23:09, 21 June 2010
Background Information
Objective: Learn about transposons and discover a brand new one all on your own
Difficulty: Medium
Estimated Time: 15 minutes
New Programs Used:
Quick Pre-Lecture on Transposons
Look to the image on the right. It is a picture of maize, commonly referred to as corn. Note how there appear to be two types of kernels, speckled and unspeckled. What do you think has caused this? If you guessed that the maize is diseased or rotting you are incorrect. The speckles are caused by transposons, non-coding segments of DNA. Transposons can be viewed as selfish sequences of DNA that are in a constant war with the coding portions of DNA. If the coding portions of DNA did not fight back with transposons, the transposons would copy themselves to make the genome extremely long. Another bad aspect of transposons replicating themselves is that they sometimes insert themselves in the middle of genes, which causes the genes to often malfunction. Luckily, there is an ancient immune system in place to fight against the transposons. Once a transposon is identified by this ancient immune system the transposon is prevented from duplicating itself.
Going back to the maize example, the kernels without speckles indicates one of two possibilities: the kernel has no transposons, or the kernel has transposons and they have been identified. With the information provided so far you are probably thinking that transposons are pure evil, but they aren't. Transposons have a noticeable role in evolution because they cause significant mutations. I use the word significant because transposons are chunks of DNA moving around and relocating, they dont create small mutations like a T pairing up with a C on accident, they are much larger.