[\/intro]Also known as Lyon hypothesis or Lyonization, this already proven theory states that in an organism with more than one X chromosome, like in a female with karyotype 46, XX, the other X chromosomes will be inactivated and converted to Barr bodies. This means that an organism with ‘n’ number of X chromosomes will have ‘n-1’ Barr bodies.[\/intro]<\/p>\n\n\n\n
This random inactivation(either maternal or paternal X chromosome) happens in somatic cells but once it happens, the chromosome will remain inactive throughout the lifetime of the cell and its offspring. It happens at the 32-cell embryonic stage.<\/p>\n\n\n\n X inactivation is the reason why X-linked diseases are more common in men than in women. X-linked diseases are diseases caused by genes that are present on the X-chromosome. In men, only one X chromosome is present so the disease will be expressed. In women, roughly half of her cells will be normal due to the X inactivation so she can live a healthy life(for heterozygous females). Details on X-linked diseases will be discussed in Genetics 2(Transmission Genetics)<\/em><\/p>\n\n\n\n <\/p>\n<\/span>Mechanism of X inactivation<\/h4>\n<\/span>\n\n\n
Significance of X inactivation<\/h4>\n<\/span>\n\n\n