Originally Posted by
MinuteMan
I'm sorry, but I have to say this is just plain false… I mean, in middle school I could have debunked this theory based on the simple steps of sexual reproduction.
The thought that a males Y chromosome comes only from the males on his sires side is incorrect. Yes his father HAD to pass the Y chromosome, as the female can only pass the X, BUT the Y chromosome the father passes down, is not a direct link to the dogs, grand father, great grand father, etc as your suggesting.
In the first stage of sexual reproduction, cells undergo Meiosis. During Meiosis, the chromosomes undergo recombination which “shuffles the deck” and creates a new gamete with a combination of each parents chromosomes.
Here is my easiest thoughts on debunking this, based on your explanation of the theory above, ALL males out of the litter would be twins. As they would be receiving the SAME Y chromosome.
Obviously this is not the case, and the reason for this is the “shuffling of the deck” of chromosomes during meiosis. Meiosis begins with one diploid cell containing two copies of each chromosome one from the dogs mother and one from its father. It then divides into four haploid cells containing one copy of each chromosome. Each of the resulting chromosomes in the gamete cells is a unique mixture of maternal and paternal DNA, ensuring that offspring are genetically different from either parent, and from siblings.
Also, during sexual reproduction, a gamete from each parent (sperm cell and egg cell) combine and fuse. Resulting in an EXACT 50/50 contribution of genes from each parent. The only reason offspring may seem to “pull” to one side or the other, is because of the contribution of dominant or recessive genes form either parent, not because on parent is making a greater contribution. This is why selection and breeding choices are key. Selecting dogs with dominant genes will pass the selected trait along. OR, selecting two individuals who both posses the SAME recessive gene, will LOCK that trait in, as there is no ther possible option for them to pas along.
All that said, I DO totally agree that female selection is of the utmost importance. As said previous, the mitochondrial DNA ALL comes from the gyp, and this does have a direct effect on energy output.
Regards,
MinuteMan