chromosome counts

A small confusion but an honest one. You've just been told that we need all our chromosomes but then told that a fusion could occur and we'd have one less yet still be viable.That sure does sound contardictory doesn't it?Here is my off-the-cuff clarification.In the case of a chromosome fusion the orginal chromosomes are still there. They are just packaged up in fewer individual pieces. In fact, the orginal ancestral chromosomes that the chimp has separate are still with us.So all the genetic material is there.In the case of extra or, worse, missing chromosomes whiich you were told is mostly fatal, the genetic material really isn't there it is missing.It is analogous to this message. If all the paragraphs were crammed into one the message would still be complete. However if the first paragraph was gone then the message would be more confusing than it is.

This is another topic I would suggest. You have some misconceptions here.