Complex sentence: In that case, a crossover event will result in one chromosome with two centromeres and an acentric fragmeentric fragment will be lost as explained above, and chromosomes with two centromeres will break unevenly during mitosis, resulting in one daughter lacking essential genes.
Split into simpler sentences: In that case, a crossover event will result in one chromosome with two centromeres and an acentric fragment. The acentric fragment will be lost as explained above, and chromosomes with two centromeres will break unevenly during mitosis, resulting in one daughter lacking essential genes.