Studies at the Stowers Institute for Medical Research have reportrf that when yeast is placed in a stressful environment that their genomes become less stable. The yeast genomes shows added flexibility involving losing or acquiring enter chromosomes so as to adapt rapidly The leader of the study Dr. Rong Li, Ph.D said "Cells employ intricate control mechanisms to maintain genomic stability and prevent abnormal chromosome numbers. We found that under stress cellular mechanisms ensuring chromosome transmission fidelity are relaxed to allow the emergence of progeny cells with diverse aneuploid chromosome numbers, producing a population with large genetic variation."
From a creation perspective this in not a problem but something that current creation science models of post Flood adaptation predicts. It shows that the animals that came off of the Ark could have quickly adapted to post Flood environment which would have been stressful.