For my new Biology course, I must answer one of the 4 questions it provided me with. So, I decided to answer the question regarding the process of genetic inheritance. It states, “Some genetic disorders are not hereditary. Give an example of one of these.”
Now there are quite a few genetic disorders that have nothing to do with hereditary genes, but how they are caused is very interesting to say the least. You see, one way cells reproduce (or split) is by “crossing over,” which is when your chromosomes exchange certain sections of themselves with one another by colliding. Most of the time these chromosomes will collide, receive their new piece, and leave; but there is a rare case where two will get stuck together and wind up on only one side of the splitting cell. This results in one cell having an extra chromosome, and the other lacking an extra chromosome. There are normally four chromosomes involved in every crossover, meaning at the end of this exchange there will be three in one cell, and only one in the other.
When there are three of the same chromosome in one cell, it causes the genetic disorder known as Down’s syndrome. There are many people who sadly have had this happen in their cells, but never the less, it is still very rare. Like I said there are quite a few other scenarios like this that can occur in your cells, but thankfully for most people, they are all very rare as well.