Why does the X chromosome inactivation occur?
Why does the X chromosome inactivation occur?
X-chromosome inactivation occurs randomly for one of the two X chromosomes in female cells during development. Inactivation occurs when RNA transcribed from the Xist gene on the X chromosome from which it is expressed spreads to coat the whole X chromosome.
What is X inactivation and why is it important?
X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells.
Why do females inactivate an X chromosome?
To prevent female cells from having twice as many gene products from the X chromosomes as males, one copy of the X chromosome in each female cell is inactivated.
Why is it important that X inactivation occur?
Why is Studying X Chromosome Inactivation Important? Many genes can undergo changes, called mutations, which, in some cases, can make a person more likely to get certain diseases. Diseases caused by mutations in genes on the X chromosome are called X-linked diseases.
What would happen if you had two Y chromosomes?
XYY syndrome is a genetic condition in which a male has an extra Y chromosome. There are usually few symptoms. These may include being taller than average, acne, and an increased risk of learning problems. The person is generally otherwise typical, including typical rates of fertility.
What happens if a person has 48 chromosomes?
48,XXYY syndrome is a chromosomal condition that causes infertility, developmental and behavioral disorders, and other health problems in males. 48,XXYY disrupts male sexual development.
Why is extra chromosome bad?
When meiosis messes up, you can end up with too many or too few chromosomes. One extra chromosome in an egg or sperm means three in the fertilized egg and so trisomy. Just like certain things increase your risk for cancer, trisomy has risk factors too. But they aren’t really things that you can control.