Wednesday, April 11, 2018

Satellite DNA = Junk DNA or is it?

Since Satellite DNA has been known about by many nicknames that have been associated with it, such as, junk, and selfish DNA. Thought to previously hold no real purpose for our function in survival. Yukiko Yamashita thought otherwise, believing that we would have gotten rid of it by now if we truly did not need it. Satellite DNA does not code for protein, so what purpose could it serve? In Yamashita's experiment she used Drosophila melanogaster and mice cells to test what would happen if you were to remove the repetitive sequencing of Satellite DNA. Yamashita and her colleges focused on D1, a protein known to bind to Satellite DNA. When this experiment was conducted on developing sperm and egg cells (germ cells) they started to die off one by one. The team later found that micro-nuclei outside of the nucleus. This meant the genome was not entirely encapsulated inside the nucleus (meaning the cell can not survive). It is believed that Satellite DNA helps chromosomes be pulled together in the nucleus ("if D1 protein cannot grab the satellite DNA, the cell loses its ability to form a complete nucleus and...dies." (1)) These experiments were then tested on mice cells and reveled the same results. Yamashita may have found the purpose to the junk we did not believe we needed.


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