I'm not sure what your argument is. Your quote includes the phrase "decrease in fertility." So let's say an organism has four (A, B, C, D) chromosomes and is t

I'm not sure what your argument is. Your quote includes the phrase "decrease in fertility." So let's say an organism has four (A, B, C, D) chromosomes and is triploid. Split the following cell into two daughter cells: A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3. Besides the fact that I don't know what a cell does when it has to try to "pair" three sister chromatids, what happens when the resulting gametes are made and then attempt to fertilize each other? You will end up with 2, 3, or 4 copies of each chromosome. This is a problem not only because how does that organism do meiosis, but also, the expression levels of the genes on the various chromosomes are going to be unbalanced. This doesn't apply to hexaploidy. >bivalent pairing during meiosis Even numbers.