Genome Entries 4

Chapter: X and Y Conflict
 
The X and Y chromosomes attracts genes that are beneficial to that sex. The Y chromosomes attracts genes that benefits the male gender such as masculine genes but the x chromosome instead attracts genes that benefit the female gender such as genes that benefit reproduction. The X and Y chromosomes always fight each other for expressions. The Y chromosome is out numbered, so it minimized itself to protect itself from the X chromosomes who numbered them times 3. An example of two genes fighting can be seen in the sexual Antagonism of Fruit Flies. When fruit flies mate, the male's seminal fluid enters the female and in the male's seminal fluid, the proteins enter the bloodstream and travels to the brain of the female. The male proteins tells the female fly to reduce her sexual appetite and increase her ovulation rate. So the male fly is trying to manipulate the female into laying eggs for his sperm and stop reproduction with other flies. This is because of the influence of the Y chromosome in the male. But the female is under selective pressure to be more resistant to the manipulation and the outcome ends in a stalemate. From this information, William Rice did an experiment in which he prevented female flies from evolving resistance while allowing males to generate more effective seminal fluid proteins. He tested the fruits after 29 generations. The results: the male sperm was now so strong that it easily manipulated the female and could even kill her.