## Friday, November 30, 2012

### Does the Bigfoot exist?

You must have noticed that two days ago, news sources were hyping a claim of Melba Ketchum, a Texan veterinarian, that she has sequenced the DNA taken from Mr Bigfoot Sasquatch Jr.

After a 5-year-long research, her DNA team in Nacogdoches has allegedly determined that he exists and he is the son of an American woman (because the mitochondrial DNA inherited from the mother matches homo sapiens sapiens) and her hairy male primate partner whose ancestors split from "us" (apologies to TRF readers who are Sasquatch Americans whom I don't count right now) about 15,000 years ago (because they are said to have discovered a new nuDNA related to humans and primates).

Oh, I see. The Register says that they claim that the sex between the human female and the exotic creature took place 15,000 years ago.

I would like some readers with some good enough background in genetics to tell me whether the claims would be possible if the hypothetical hairy 8-feet Gentleman exists and, more generally, what is the most likely explanation of all these claims. Thanks...

Before I am told something more sensible, I find the story very unlikely and the source doesn't look excessively credible but the story is not impossible. It doesn't seem to be banned by the laws of Nature that there could be a primate that's closer to us and whose population is very small – and the remaining ones are dying in car accidents every year. However, it's even more suspicious that this is supposed to be offspring of humans with a primate that is unknown.

1. South Park did a thing on that.

2. Do you mean the Manbearpig or something else? I guess the number of DNA technicalities in the TV show wasn't enough to satisfy me haha.

3. I don't know if it is more or less implausible than superluminal
neutrinos. I'd have to say more, but both are pretty implausible, and
that's putting it more politely than it deserves. At least the neutrinos
were an honest error that anyone could make.

There are several obvious explanations: contamination, incompetence, a deliberate hoax, or all three.

Human
DNA, especially mitochondrial DNA, is found on anything a a human has
ever touched or breathed on. Finding human mtDNA in a sample is as
significant as a 0.3 sigma signal.

It is less obvious where the got the monkey, or gibbon, or whatever.

Seriously, there are so many things wrong with the whole Bigfoot thing that I don't know where to start.

4. That there might have been "another hominid" isn't all that unlikely. As late as 20,000 years ago, there was a large number of "another hominid" - Neanderthals.

"Crossing" isn't that unlikely either. Most Europeans and Asians have some Neanderthal DNA. A few percent for most of us. ( I think I have a few more than most, given the Neanderthal traits I can identify in me ;-)

Asians also have some amount of Denisovan DNA.

http://www.bbc.co.uk/news/science-environment-12059564

A rare hominid from Siberia.

Now, whats the most likely explanation for the DNA result in the 'test'?

Genetics is not nearly so "clean" as folks like to think. We are all, every one of us, a unique collection of 'odds and ends' from the last 4 Billion years. Some bits, like the Citric Acid Cycle, are fairly strongly conserved. Others, more chaotic. So most likely is just that it's human DNA from a person who hung onto an old gene in that position. The second most likely would be that someone mixed a bit of Chimp DNA with human and planted the 'sample' as a hoax. (Though anyone with a clue would have caught that by looking at the sample closely and looking for any differences in chromosomes from cell to cell... but if they didn't look...)

There were many OTHER hominids in the not too distant past, and any of them might have hung on in a minor population 'in the boonies'. If you have good hearing and don't want to be found in the forest, it's pretty easy to avoid most people who can't keep quiet if they try, and they don't try...

That said, I doubt, strongly, that there's a real yeti / sasquatch / Big Foot / whatever. (BTW, the "iconic" video you show of a Big Foot walking... the guy who was in the furry suit has come forward and said he did it... ) A "hoax" is far more likely.

5. I thought it was all nonsense until I saw one ten years ago from a distance of about 50 meters for 7-10 seconds. What I saw and where I saw it leaves no other real possibilities.

6. The story of the Bigfoot hoaxer being run over by passing motorists is surely the most hilarious I have read in a long time. Its sad that hoaxers aren't rewarded for their efforts in such a grotesque fashion more often. We can only celebrate on the rare occasions when it happens.

7. Come on, it's surely way more plausible than superluminal neutrinos or any other superluminal thing.

Particles faster than light contradict a pillar of physics justified by a totally natural symmetry that can't appear accidentally tested with accuracy of a dozen of significant figures. Bigfoot is just some new race/monkey.

The more nontrivial thing than the human mtDNA is clearly the new nuDNA if it's there.

8. On the British program, QI, one guest mentioned that he had travelled throughout the world and found stories about a "Big Foot" from the USA to China, Sibera ... . So the story is widespread but that may not mean much because like mythologies can occur across the globe. He also made the point that it was not that long ago we discovered the mountain apes in Rawanda.
Humans mating with primates. Well perhaps the Siberian sightings can be explained by Stalin's insistence on impregnating human females with gorilla sperm to produce super soldiers. There is the problem of that extra chromosome though ...

9. It could be acromegaly(giantism)

http://emedicine.medscape.com/article/925446-overview

One of the key distinctions in the hominid line is the movement from heavy set to "gracile". Even Cro Magnon was a huge chap by our standards.
The big problem is no clear evidence. As someone once joked(South Park?): why don't they just place internet linked cameras in the relevant forests? The reply: people who report these things typically aren't rich enough or sufficiently well informed to do such a thing.

10. You say a "problem". So is the human-chimp hybrid baby possible or not?

11. Are you serious? And by the way, please don't get offended, is the avatar you use yourself or the creature you have seen? ;-)

12. Or they know that the cameras wouldn't see anything...

13. I think the extra chromosome would be catastrophic. It is estimated that perhaps only 1 in 3 human fertilisations go to term, most miscarry, this sometimes mediated by the female immune system rejecting the proteins produced. Many sperm are believed to be eliminated by the female immune system long before reaching the ovum. So you would either have a genetic catastrophic or an immunologically driven abortion. However inter-species fertilisations can occur between closely related species. See:

http://everything2.com/title/Interspecies+breeding

My understanding is that such interbreeding won't produce fertile offspring, they remain sterile. That may not always be true, it is conceivable that modern humans did interbreed with archaic hominids and recent genetic studies do find traces of Neandertal and Devisonian genes. See:

http://www.newscientist.com/blogs/shortsharpscience/2010/04/early-humans-may-have-bred-wit.html

14. Thanks, I understand the immunity system reaction, if it is true, although I am not quite sure how the immunity system counts the chromosomes etc. from the resulting proteins.

On the other hand, I don't understand what a "genetic catastrophe" is. Could you please describe in some more detail what would actually happen in this "genetic catastrophe"?

15. The immune response has nothing to do with the chromosomal issue. Two different ways for fertilisation to fail. The genetic catastrophe occurs because the extra chromosome in one species has no match in the egg or sperm. Cells undergoing division have "checkpoints", if there is a fail at this checkpoints the cell cycle is interrupted and the cell undergoes apoptosis - programmed cell death. The division process is carefully orchestrated. With the extra chromosome you'll get a fertilisation failure because it has no other chromosome to pair with, hence the mitotic spindle will not form correctly. That is a signal for cell death. Thus ...

For instance, a human germ cell (a sperm or an egg cell) is haploid, which means it contains only one of each of the 23 chromosomes of the human genome, or it only has half the diploid (2n) number of a human somatic cell (which is 46). Gametes being haploid are essential particularly during fertilization. The union of two sex cells, each with only haploid number of chromosomes, results in a diploid zygote. The integrity of chromosomal number throughout generations is eventually preserved.

With an immune response rejection can occur for a number of possible reasons. Even the sperm of a male can be attacked by the female immune response. The fertilisation can also go awry leading to aberrant protein production or a deformed fertilised cell which can then be subject to either poor implantation in the tube or immunological destruction.

You are stretching me here Lubos, long time since I studied this. BTW, glad I found your blog. Thanks.

16. Thanks, that's very interesting. Does the suicidal behavior of the "cells in trouble" help the genes/organisms to survive at some point and if it doesn't, how did it evolve?

17. Apoptosis occurs even in single celled organisms. I could never understand why it exists in bacteria until I thought of bacteriophages - viruses that infect bacteria. By undergoing apoptosis the cell prevents viral replication and the eventual bursting of the cell which causes the spillage of viral particles into the surrounding area hence leading to infection of neighbouring cells.

Apoptosis happens all the time. Cells do not always divide well and if there is a checkpoint fail the cells undergo apoptosis as a means of preventing the creation of aberrant and potentially cancerous cells.

The midpoint is cell senescence, where a damaged cell, put simply, goes to sleep. The problem here is that these types of cells also release inflammatory mediators and "danger signals", which can damage surrounding cells and make otherwise healthy cells subject to immunological assault. As one recent study highlighted, in alzheimers the problem might be so many damaged cells in senescence that these drive alzheimers by increased apoptosis and inflammation mediated damage.

There are different forms of apoptosis and in bacteria is not quite like in multi-cellular creatures. Failure of apoptosis is strongly implicated in cancer. Apoptosis is also involved in growth processes, where a great many cells can undergo programmed cell death as way of "pruning" excess cells. In the human brain massive apoptosis occurs circa one year after birth and then a less marked cell loss at the onset of puberty. One striking study I read years ago showed how in schizophrenia, this second onset of apoptosis is much stronger than in other individuals though why this happens remains unclear. This second period of apoptosis has clear implications for children: teach your children well! It is believed that children who are intellectually active at this time will have significantly reduced neuron cell loss by apoptosis at this time point.

18. Excellent, thanks a lot, very informative.

19. Just some new race/monkey that is immortal, or vanishes when it dies like "Buffy" vampires. That (unlike Bigfoot hunters) never gets hit by cars, or shot (rednecks are common in the region, and very good shots), and can only be photographed out of focus.

The biology might seem more plausible to someone who knows less about it, just as superluminal anything might seem more plausible to someone who knows less physics, but really they are both extremely
implausible.

So implausible you can't ignore the a-priori probability that the universe was intentionally designed to deceive physicists.

20. OK, it doesn't look extreme to me. How many gorillas get hit by a car or are photographed outside zoo? How plausible or implausible it is that there has been a primate species whose population is 100 times smaller than gorilla's that survived for 15,000 years? It doesn't seem implausible to me at all. I don't believe there is some extra secret knowledge that professional biologists know that could change the conclusion.

21. Google found *lots* clear of images of Mountain Gorillas, which are not kept in any zoos. The total population of that subspecies is estimated at 620, and is probably not viable long term. I'm pretty sure a population of 0.62 is impossible. Their habitat is much more remote than Bigfoot's (which is a 3 hour drive from my office).

Basic biology isn't any more "extra secret" than Lorenz invariance.
Could there be an undiscovered species of monkey in some jungle miles from the nearest road? Sure.
A human-ape hybrid in eastern North America? Not a chance.

22. You may be right. Or not. The November 2012 population of Mountain Gorillas is 880. I would still bet that you will find pictures of much fewer than 880 mountain gorillas, so most mountain gorillas remained "not yet clearly seen". So if the number of bigfoots is of order one, it's still compatible with his not being seen yet.

One doesn't even need any basics of biology here. It's about the basic counting of probabilities.

I am not saying I believe it's likely that bigfoot exists; but I am surely saying that you confuse the certainty that only physics may achieve with some plausibility arguments that may be good enough to convince people about one point of view or another. These are at completely different levels. The probability that five bigfoots somewhere would be compatible with all the data - lack of evidence - may be something like 0.01%. But the confidence with which we could have excluded e.g. the superluminal OPERA neutrinos was sure more robust than 0.0000001%.

23. let me guess. You're bigfoot sighting took place in your bathroom mirror.

24. He is Andre the Gentle Giant (Andre Rene Roussimoff) from Grenoble, France. He is well worth a little research. My own visage is much more road worn than that. :-)

And, yes indeed I saw something in the Santa Cruz mountains a mile or so from Camp Cutter to which I could overlay no template from my experience. It was cool watching my brain try to do that and fail.

In many ways it was prototypical of the sightings reported the world over. I was driving slowly down a rutted dusty road in the woods following a four day jamboree at the mountain camp with a couple hundred "New Age" folks doing strange (sober) things. I'd stayed behind for some final clean up and was the last one out by a couple of hours. I entered a clearing to see lt lope across the road in front of me. It ran on all fours but the body geometry (hind held high) and its articulation bespoke a normally standing hominid in a hurry. I haven't seen many things lope but it loped. It was a dark redish brown and was much thinner and lankier than the pictures and drawings I've seen. Wads of clumped, attached hair streamed off of it, especially at the rear. The only thing that could have been there that might have approached its size would be a horse and a horse it definitely was not. It crossed the road maybe 30 yards in front of me and turned to come back by me in the woods to my right. I stopped the car as soon as I saw it and watched. The woods beside me was sparse and I watched it until it was behind me and swallowed up by undergrowth.

That's as far as the story goes and as much as I know but I'll swear by it. It left me trembling.

25. It's amazing ! Couldn't it have been some kind of wild boar ?

26. A population of order one isn't possible for long. The smaller the population the more they are affected by fluctuations. For instance, in a population of five, each generation has a 1/16 chance that all five are the same sex, game over. That's not the limiting factor, fluctuations in gene frequencies put a bigger lower limit on the size of a viable population.

But let's assume your 0.01% for bigfoot (still a bit high, If you give me a penny, I would probably be happy to promise you \$100 if bigfoot is found). Even if bigfoot were known to exist, "Bigfoot is a hybrid of a human woman and an extinct North American primate" would still be in perpetual motion machine territory, with plausibility at most 1 in a million (it would take pages just to *list* the reasons, to say nothing of defending them).

0.01% * 10^-6 = 0.00000001% which is less than your 0.0000001% for superluminal neutrinos (which I also think is too high).

27. Right, I am aware of those things. The population didn't have to be this tiny for a long time. It may just be that it converged towards 3-10 in a recent century. It's OK to sustain the population like that for a century. Assuming that there's a moment in which they converge towards extinction like this, the probability is 1/150 that among the 150 centuries that they're claimed to have gone through, the "doomsday" century is the 20th one. So one could design a scenario in which one assumes two or three assumptions like that, each of which has a probability 1/100 to get through.

You may get more extreme numbers but that's because you're not considering the most optimal ways for the Bigfoot population to survive and agree with the current data at the same time. In some sense, your arguments look very similar to what I've heard from creationists during our brainstorming in Nice. When they prove that evolution can't work - and be sure they're very clever and detailed and quantitative in such criticisms - the error always boils down to their considering a model of Nature that isn't optimal and pretending that it's the ultimate bound. However, Nature often does better and uses various tricks, e.g. adjustment of mutation rate, recycling of parts of body from other things, and so on.

But of course, I am not discounting your arguments. Of course I would be ready to bet against Bigfoot in the same way as you did, too.

28. As big as a horse? There are in fact wild pigs in the area (and possibly wild things that long ago escaped from W.R. Hearst's zoo down the coast a ways) but it in no way resembled a pig.

29. Here are some scientific analyses showing Bigfoot isn't real:

http://thoughtsonscienceandpseudoscience.blogspot.com/
thought you might find interesting....