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.

REFERENCES:
(1) https://www.sciencedaily.com/releases/2018/04/180411131659.htm
(2) https://elifesciences.org/articles/34122

New Technology Applied to Studdying Nuclear Pores

Scientist have recently begun putting a new technology to use to study the micro-physiology of our cells.  With the aide of an atomic force microscope (AFM), researchers from Basel University have been able to observe the nuclear pores that control traffic through the nucleus of a cell.  The most notable discovery from this research was the ability of these pores to prevent unwanted chemicals from entering the cell.  This was observed via microscopic tentacles that monitor movement in and out of the nucleus.  The AFM does not work like any regular microscope.  This machine uses a fine-tipped feeler to sense the environment in which it has been emmersed.  This method and information could prove incredibly useful for the study of carcinogens and how they enter the nucleus.

Where Did Your Pet Dog Originate From?

Originally, scientists had evidence of the household dog being traced back to ancestors of the gray wolf in Europe, Siberia, the Near East, and South China.  However, recently, scientists Laura M. Shannon and Adam R. Boyko from Cornell University, as well as other international scientists, did a large study on dogs all over the world, including purebreds and village/street dogs.  They took three different types of DNA, to account for such a large and diverse population of 4,500 dogs of 161 breeds and 549 village dogs from 38 countries.  This assortment allowed "the researchers to determine which geographic groups of modern dogs were closest to ancestral populations genetically" (NY Times).  Their findings: that dogs originated and were primarily domesticated in Central Asia.  Their techniques for these findings were very similar to the techniques used in order to find out that humans originated in East Africa.    "The team analyzed DNA from all the chromosomes in the cell nucleus, from the Y chromosome specifically, found only in males, and from mitochondria, cellular energy machines outside the nucleus that are inherited from the mother" (NY Times).  Originally, they had expected their results to be "messy," however, instead all of the DNA seemed to follow the same pattern.  In their analysis, they explain the location of the origination, and also explain that the time of origination cannot be precisely dated; however, there is evidence of at least 15,000 years of the domesticated dog's existence.

I found this article very interesting, not only because I have a dog of my own, whom we've always questioned her mix of breeds, but also because within the first week of class we discussed the different domestication of animals and where they originated from.  This discussion included the domestication of dogs and we spoke about how they originated in Europe, and now, just within a few weeks to a month, our whole perspective is changed.