what is lyonisation

Lyonization, also known as X-inactivation, is a process by which one of the two X chromosomes in every cell of a female individual is inactivated during embryonic development. This process prevents females from having twice as many X chromosome gene products as males, who possess only a single copy of the X chromosome. Lyonization was discovered by British geneticist Mary F. Lyon, and it is named after her. In this process, an X chromosome is compacted into a small, dense structure called a Barr body, and most of the genes on the Barr body are inactive, meaning that they are not transcribed. Lyonization can be important in clinical genetics, as it can affect how X-linked conditions manifest in different individuals.