Science behind XY and XX chromosomes in human being

Washington, DC: A recent study has revealed the evolution of X chromosome and why it contains an unusual mixture of genes.

In humans, males have XY chromosomes, females have XX but only one of these is active, meaning that both sexes only have one active copy of the X chromosome.

Scientists discovered in 2002 that the X chromosome is unusual because it contains very few of the most important genes needed for basic cell function, dubbed 'housekeeping' genes.

Now the team led by Professor Laurence Hurst have analysed the world's largest compendium of data on gene activity (expression) and looked at how activity on the X chromosome compares with that on other chromosomes.

The team also identified which genes have moved from the X to the other chromosomes over evolutionary time and those that have gone the other way.

This study has been published in PLOS Biology.