Ok would back crossing with the species with the larger chromosome set not fill up the number of chromosomes to the same level as that parent species?
As in pre-human (post-chromosome fusion event) 46 chromosomes crosses with pig 38 chromosomes.
so 23 + 19 = 42 chromosomes in say a female offspring.
That hybrid mates with another 46 chromosome pre-human.
So 46/2 + 42/2 = 44 chromosomes, this offspring then mates with another 46 chromosome pre-human.
So the resulting hybrid is 46/2 + 44/2 = 45 chromosomes.
Yet another backcross and we get.
46/2 + 45/2 - Now I think if one divides 45 chromosomes in half you should either get 22 or 23 chromosomes in the gamete because chromosomes are not chopped in half only separated from their pair. So this combination would result in either 23 + 23 or 23 + 22. If this mating involved 23 + 23 then the chromosome count is restored to 46.
It could but you still have all those nasty fertility problems, so when you back cross into a larger population who is more fertile you will be out competed and your genes will be selected against until they are removed from the gene pool.
Once one has the hypothesis that a species is a hybrid, surely morphology is the first approach to identifying potential source species?
Before the advent of molecular biology sure, but nowadays you look at the gene and protein level first.
Once you have narrowed down which species are likely sources you can then do the molecular biology to confirm it.
I'll point out that molecular biology has already disproven the hypothesis, a pig is no more related to us than it should be given it's evoloutionary distance.
Let's say some one gave you a zedonk for christmas but couldn't tell you anything of its lineage. You thought it looked a bit odd and that maybe it was a hybrid, what do you do now? Would you a) compare its genetic code with every other species on the planet? Or b) notice that the zedonk had zebra characteristics and donkey characteristics and then compare its genome to that of zebras and donkeys?
To guess sure, but you don't found a hypothesis on that. You have to do an experiment based on your hunch to actually publish something like this. To prove something like this you would need molecular biology. Part of what annoys me about this hypothesis is that he didn't even do basic experimentation before he tried to popularize his idea with the public, which is a huge no no.
McCarthy addresses convergence in his hypothesis. He says that convergance can reproduce the macroscopic similarities but not fine detail similarities (I am paraphrasing).
That's not true, every detail of the body is created by evolution and can be convergent. This is also part of where I say he cherry picks, he looks at everything about us that is very similar to pigs, and ignores anything significantly different.
So for example dolphins converged on the fish morphology macroscopically ie: sleek form and limbs that are paddle and fin like. But that convergance did not and could not reproduce scales and gills and what not.
Very true, and we have some similarities to pigs, but we walk upright and a quite a bit more intelligent and don't need to wallow in mud.
McCarthy claims that the morphological similarities with pigs extend to the fine detail more than they do to the macroscopic. Moreover there isn't any selection pressures that could cause humans to converge on those pig features. What selection pressures would give humans extra tail bones over chimpanzees for example?
We aren't descended directly from chimps, we share a common ancestor with chimps. Chimps had a tailbone fuse to their sacrum in their evolutionary history and we didn't.
Mitochondrial DNA comes strictly from the mother, so if it's chimp mtDNA (which it wouldn't be, it would be the common ancestor between chimps and humans) then that wouldn't really prove anything about the pig thing.
My dream is a hemispheric common market, with open trade and open borders.