Chimp/pig hybrids evolved to humans? Part 2:

http://phys.org/news/2013-07-human-hybrids-closer-theory-evidence.html

The original story I pushed here had a lot of flack and positive feedback also.

Originally posted by sonhouse
http://phys.org/news/2013-07-human-hybrids-closer-theory-evidence.html

The original story I pushed here had a lot of flack and positive feedback also.

This is still total bunk. It's about the same level as the worry about LHC destroying the world. All the examples of hybrids are from animals within the same tribe (the goat-sheep hybrid is the only example of an animal hybrid I know of not in the same genus). The division is:

mammalia -> Boreoeutheria -> Euarchontoglires -> Euarchonta -> Glires -> primates -> apes -> us
mammalia -> Boreoeutheria -> Laurasiatheria -> Cetartiodactyla -> Artiodactyla -> suina -> pigs

There is simply too much distance. If it was that easy to produce hybrids we'd be up to our ears in mad crosses. Aside from anything else bestiality has been forbidden since the most ancient law codes, which means it happened enough that they legislated against it, so if a hybridization was possible between any primate and any ruminant it would have happened by now.

This is from the code of the Nesilim (The oldest surviving law code and a bit of a hoot):

187. If a man have intercourse with a cow, it is a capital crime, he shall die. They shall lead him to the king's hall. But the king may kill him, the king may grant him his life. But he shall not approach the king. [I should think not!]

199. If anyone have intercourse with a pig or a dog, he shall die. If a man have intercourse with a horse or a mule, there is no punishment [!!!]. But he shall not approach the king, and shall not become a priest. If an ox spring upon a man for intercourse, the ox shall die but the man shall not die. One sheep shall be fetched as a substitute for the man, and they shall kill it. If a pig spring upon a man for intercourse, there is no punishment. If any man have intercourse with a foreign woman and pick up this one, now that one, there is no punishment.

I asked a doctor who sometimes turns up on Tuesdays for chess, and he asked a friend who works on Zoonosis for the Ministry of Health, his opinion was that horses were the most dangerous from an infection point of view...

McCarthy's refused to make a hybrid on ethical grounds, which is ridiculous given mouse/human crosses are used to test fertility. You just stop it growing after a month or so. He needs to show a chimp/pig cross could 1) form a zygote, which isn't certain, the sperm may not bind, and 2) start dividing and get past the stage where the notochord forms (there's some really tricky moments before that). I bet 2 can't happen, the embryo would just terminate.

Fundamentally though, the burden of proof is on him as he is making the claim, it's not up to the rest of the scientific community to prove him wrong until he's come up with some real evidence for this instead of a list of anatomical similarities.

Originally posted by DeepThought
This is still total bunk. It's about the same level as the worry about LHC destroying the world. All the examples of hybrids are from animals within the same tribe (the goat-sheep hybrid is the only example of an animal hybrid I know of not in the same genus). The division is:

mammalia -> Boreoeutheria -> Euarchontoglires -> Euarchonta -> Glires ...[text shortened]... come up with some real evidence for this instead of a list of anatomical similarities.

They talked about putting their money where there mouth is by actually doing the chimp/pig hybrid. I see a Debra has just been made, Donkey and Zebra, so hybrids do happen. They called it a Zonkey but I call it a Debra🙂

They cited ethical concerns with actually doing a chimp/pig hybrid. Of course you would not need for the two animals to actually have sex, it could be invitro.

Originally posted by DeepThought
Fundamentally though, the burden of proof is on him as he is making the claim, it's not up to the rest of the scientific community to prove him wrong until he's come up with some real evidence for this instead of a list of anatomical similarities.

I think this is the heart of the matter. Physical similarities simply are not enough. My sister told me that one of her lecturers pointed out that when describing a mammal:
It has fur.
It gives milk.
It has a hard skeleton.
- you haven yet ruled out the coconut!

These days it is trivial to sequence the DNA and it should be trivial for him to demonstrate the existence of pig genes in humans that are not in chimps. That he hasn't done so tells us that he doesn't believe his own claim.

Originally posted by sonhouse
They talked about putting their money where there mouth is by actually doing the chimp/pig hybrid. I see a Debra has just been made, Donkey and Zebra, so hybrids do happen. They called it a Zonkey but I call it a Debra🙂

They cited ethical concerns with actually doing a chimp/pig hybrid. Of course you would not need for the two animals to actually have sex, it could be invitro.

My main point is that McCarthy's trying to reverse the burden of proof. It's up to him to show that it is possible (which he hasn't) it's not up to the scientific community to prove him wrong. His theory is difficult to disprove because he's hardly said anything, other than list some anatomical similarities, there isn't a concrete position to refute. You'll note the article says:

"One thing we have not heard here is objection from those writer-scientists who have any kind of public reputation in the evolutionary sciences."

or in other words they aren't interested enough to bother shooting it down.

Hybrid fertility isn't straightforward. The edible frog is a hybrid between a Pool Frog and a Marsh Frog. If it mates with a Pool Frog you get Edible Frog tadpoles, if it mates with a Marsh Frog you get Marsh Frog Tadpoles, and if it mates with another Pool Frog it produces non-viable tadpoles. See the Wikipedia article on "Edible Frog". It matters how the gametes work out. Even if a hybrid is possible it may only be able to have offspring in that kind of pattern. So even if a hybrid is possible an independent population is not automatically viable.

Incidentally if the mother was the pig then it should stand out like a sore thumb in mitochondrial DNA (provided there's a sequence of "Eves" until the pig/chimp hybrids became a stable population).

And finally, the similarity between platypus DNA and bird DNA they mention in the article is evidence that some of the genes associated with laying eggs are highly conserved and is not evidence of hybridization, unless you can point to an ancestor of platypuses which definitely didn't have them. The reason is that if the egg laying process goes wrong then the offspring aren't viable so I'd expect these genes to be in any amniotes where they haven't been rendered irrelevant by a placenta or pouch. I am willing to bet that if they sequence Echidna they'll find the same genes.

Originally posted by DeepThought
And finally, the similarity between platypus DNA and bird DNA they mention in the article.....

I found it funny that they thought the bird genes would be from a duck-like bird. Its as if they actually think the platypus' 'beak' is produced by bird beak genes.

Incidentally, at the bottom of the article referenced in the OP there's a link to this page: http://www.ensembl.org where you can browse the entire human, chimp, and pig genome, as well as platypus, various birds, but sadly not echidna.