What would happen if chromosomes didn't cross over?

Answer 1

One cell would receive all the DNA, and the other would receive none. The one that receives no DNA would die since the cell needs an intact genome to function, and the other cell would probably die too. Having too many copies of chromosomes can be fatal, and I would expect that having double the needed DNA would kill the cell.

Answer 2

If chromosomes didn't cross over during meiosis, genetic recombination between homologous chromosomes would not occur. This would lead to reduced genetic diversity in offspring, potentially increasing the likelihood of inherited disorders and limiting the ability of a population to adapt to changing environments.

Answer 3

You would have no variety in the organism.