So, say I get a set of chromosomes from my Mum which contains the X chromosome and the same from my Dad, but with the Y chromosome. I now have two sets of the same 22 chromosomes, plus an X and a Y.

For chromosome number one for example, is everything from my Dad’s side activated? My Mum’s? Or is is a random selection of genes within each chromosome?

And does the X chromosome do anything for me, or is it turned off, and only used if I pass it on to the next generation?

Follow up question: I believe that women actually recombine their X chromosomes when passing these on, but men can’t recombine X and Y. So everything on your Dad’s side stays the same. Does this have any impact? For example are you more likely to inherit genetic defects from your Dad’s side?

  • Basic K12 biology didn’t go into deep details; OP is asking, I think, what decides which genes are combined. You can only get at most half of each from the parents - you don’t get all of each - so what exactly selects which genes from each are combined?