The Y chromosome isn't going extinct after all!

            Previous research has suggested the Y sex chromosome, which only men carry, is decaying genetically so fast that it will be extinct in five million years. David Page, the director of MIT's Whitehead Institute, has spent the last decade trying to prove this wrong. He compares the Y chromosome of the Rhesus macaque, a monkey that diverged from our evolutionary ancestors about 25 million years ago.  When Page did this research he found that the Rhesus Y chromosome has not changed for 25 million years. On the other hand our chromosome has lost 3% of a small segment of the Y chromosome. A genetic professor Brian Sykes predicts the demise of the Y chromosome, in as little as 100,000 years in his 2003 book Adam's Curse: A Future without Men. But luckily men aren't going to be gone for a long time.

I really liked this paper just from the title alone. It drew me in and I had to read it. It was interesting to know that Page compared our chromosome to Rhesus monkeys and found similarities. Another cool fact was that the Y chromosome has 78 genes while the X chromosome has 800 genes attached to it. That fact blew my mind and hopefully yours as well.

Two Mothers, One Father

Karen Weintraub's article was published in The New York Times on December 16, 2013. At this time, Alana Saarinen was thirteen years old. Sharon and Paul Saarinen are her parents who gave the egg and sperm that created Alana. Sharon has a rare mitochondrial disease so another woman donated her genes that were used to allow Alana to be born with normal mitochondria. Alana has nuclear DNA from her mother and father, and also has mitochondrial DNA from a woman donor. This was done by a process known as cytoplasmic transfer. Mitochondrial diseases are rare. It only occurs in about nine to twelve out of every 100,000 people. The rare disease is passed from mother to child. Fertilization techniques, such as cytoplasmic transfer, prevent the children from inheriting the mitochondrial disease from their mother. Another technique is to insert the nuclear genome from the mother into a donor egg which would be fertilized by the father's sperm. The egg could also be fertilized before the nuclear genome is inserted. Cytoplasmic transfer was halted by the Food and Drug Administration in 2001 for not having been officially approved. They stated in 2012 that, "This crosses a line drawn by many scientists and bioethicists at altering the genetic profile of unborn children". Many scientists in the United States, as well as the United Kingdom, want these processes legalized. They argue that there has been no evidence that it is harmful and that these techniques allow mitochondrial diseased woman to produce healthy, biological offspring. Opposers of the processes being allowed think that there have not been enough studies done and that it is genetic engineering. Some scientists believe that mixing two woman's DNA into one child is unethical. A study on mice suggested that mice with mixed mitochondrial DNA may have a higher risk of mental impairment, obesity, and disease. New techniques are currently being worked on so that they will be safer. Instead of using just parts of a donor's mitochondrial DNA, scientists have begun to use all their mitochondrial DNA. A recent study concluded that all Rhesus monkeys born with replacement mitochondrial DNA are normal and healthy. Alana was also born healthy and has never had any serious health issues.

Cytoplasmic transfer is just one way that allows woman with a mitochondrial disease to have healthy, biological children.

This is a great advancement in science. Ethical issues will always play a role anytime we manipulate human life and genetics. I agree with the FDA that this needs to get official approval but I do not see that being an issue for the scientists involved. They already have healthy, normal children, such as Alana, as a product of cytoplasmic transfer. With the work they have done since 2001, they now have a better understanding and have developed new, safer techniques. If there are no serious risks then why not allow a mother with a mitochondrial disease to have biological children?