Hope you had a great Christmas. Yes, always last minute shopping for the wife. Found out this is very dangerous online - arrived in the mail Christmas eve - much too close.
Gene doubling and chromosome doubling can change the organism. Sometimes the increased number can increase the number of proteins which can be either harmful or beneficial. However, as we discussed earlier, what is interesting is when the duplicated gene mutates, then there is a backup gene to perform the original function while the new gene can produce a possible new function. As I stated before...
I think we are talking across each other here. Yes, I agree that mutations, gene doubling, chromosome doubling etc CAN and usually IS harmful and often lethal.
However, when they are lethal, they are instantly removed from the gene pool. The rare beneficial one multiplies through the gene pool. Plant breeder have created a whole host of useful plants by using polyploidy. I am sure that the vast majority of attempts by plant breeders were failures. But the rare successful ones became extremely popular.
This artificial form of selection is typically much faster than natural selection, but the basic idea is the same. Harmful, mutations are removed. The rare beneficial mutation multiplies.
I have been gone for a long time. I justed want to give an answer before the thread died.
I see that polyploidy are used frequently in improving our domestic plants. I don't know if the plants in the above are do to genetic manipulation or forced mutations. Because the plants can not reproduce, I would guess these plants are good for the farmer but are not a step forward in the evolutionary process.
Anyway, I will try to unpack this latter. I hope you and your family are fine. I am also interested to see if you found any interesting fossils.