Have YOU been tested for Neanderthal genes?

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Hmm, the study I read must have been really old then. I know about the recent uptick in autism rates for black people in America, though. FYI, I meant people still living in Africa. Though my googling states the rate of autism in Africa as unknown, I do remember having read that it is very low.

There are recent studies that suggest that the risk of autism in children increases if the mother had low levels of Vitamin D when pregnant.

Assuming such a link turns out to be true, it would not be useful to compare rates between one group in Central Africa and another in Northern Europe.

Source please? Would like to read that. Even if there would be a correlation between low levels of vitamin D and autism, at most that would be because almost every single person in northern Europe have low levels of it. So, did they check the level of autism in northern europeans living outside northern Europe, too? I doubt epigenetics have anything to do with autism, and I doubt low levels of any vitamin could change the brain structure that much but it does sound interesting.

In this case, it doesn't appear to be the case of Vitamin D making any changes to the brain structure making them autistic. Rather, it is the Vitamin D levels of the pregnant mother. I don't know if there is any hypothesis regarding the mechanisms involved.

Here's a recent thread on the subject: http://www.wrongplanet.net/postt219385.html

Thanks, read it now. So it was only in the US? Wonder if were the settlers from different nationalities went could have anything to do with it. Didn't many from northern Europe emigrate to the midwest and northern parts of the US though?



"Distribution of Swedish Americans according to the 2000 census"

He DID talk about brain development, but not what the changes were:
Animal models of vitamin D deficiency during pregnancy have also shown that low levels have a definite effect on how the brain develops, and the same may be true for humans, although that is speculative, he added

Don't think low levels of vitamin D would give someone double the amount of neurons, and if it would then whoa, free sunscreen for all!

The research reported in the article was done in the US. I would be surprised if there were no studies of the effects of Vitamin D on neuroembryology being conducted in other countries as well.

There is nothing to indicate that the observed effect is somehow limited to the US.

No, but the study was done in the US, is what I'm getting at. Also, if they got the results based on the europeans settling in places were there is less vitamin D, and then getting lots of autistic children (as the rate is higher in Europe and autism is genetic and hereditary and probably can't be influenced by epigentics like vitamin-levels, or mercury, or whatever is the flavor of the day), then that does matter.

Developmental vitamin D deficiency causes abnormal brain development.

...

Abstract
There is now clear evidence that vitamin D is involved in brain development. Our group is interested in environmental factors that shape brain development and how this may be relevant to neuropsychiatric diseases including schizophrenia. The origins of schizophrenia are considered developmental. We hypothesised that developmental vitamin D (DVD) deficiency may be the plausible neurobiological explanation for several important epidemiological correlates of schizophrenia namely: (1) the excess winter/spring birth rate, (2) increased incidence of the disease in 2nd generation Afro-Caribbean migrants and (3) increased urban birth rate. Moreover we have published two pieces of direct epidemiological support for this hypothesis in patients. In order to establish the "Biological Plausibility" of this hypothesis we have developed an animal model to study the effect of DVD deficiency on brain development. We do this by removing vitamin D from the diet of female rats prior to breeding. At birth we return all dams to a vitamin D containing diet. Using this procedure we impose a transient, gestational vitamin D deficiency, while maintaining normal calcium levels throughout. The brains of offspring from DVD-deficient dams are characterised by (1) a mild distortion in brain shape, (2) increased lateral ventricle volumes, (3) reduced differentiation and (4) diminished expression of neurotrophic factors. As adults, the alterations in ventricular volume persist and alterations in brain gene and protein expression emerge. Adult DVD-deficient rats also display behavioural sensitivity to agents that induce psychosis (the NMDA antagonist MK-801) and have impairments in attentional processing. In this review we summarise the literature addressing the function of vitamin D on neuronal and non-neuronal cells as well as in vivo results from DVD-deficient animals. Our conclusions from these data are that vitamin D is a plausible biological risk factor for neuropsychiatric disorders and that vitamin D acts as a neurosteroid with direct effects on brain development.

McCann & Ames point out that evidence for vitamin D's involvement in brain function includes the wide distribution of vitamin D receptors throughout the brain. They also discuss vitamin D's ability to affect proteins in the brain known to be directly involved in learning and memory, motor control, and possibly even maternal and social behavior. The review also discusses studies in both humans and animals that present suggestive though not definitive evidence of cognitive or behavioral consequences of vitamin D inadequacy. The authors discuss possible reasons for the apparent discrepancy between the biological and behavioral evidence, and suggest new, possibly clarifying avenues of research.

Evidence for the presence of the vitamin D receptor in brain implies this vitamin may have some function in this organ. This study investigates whether vitamin D3 acts during brain development. We demonstrate that rats born to vitamin D3 deficient mothers had profound alterations in the brain at birth. The cortex was longer but not wider, the lateral ventricles were enlarged, the cortex was proportionally thinner and there was more cell proliferation throughout the brain. There were reductions in brain content of nerve growth factor and glial cell line-derived neurotrophic factor and reduced expression of p75NTR, the low-affinity neurotrophin receptor.

Our findings would suggest that low maternal vitamin D3 has important ramifications for
the developing brain.

...

In this study, we investigated whether vitamin D3 deficiency during gestation could alter brain development. Our results indicate that gestational vitamin D3 deficiency has profound effects on the developing brain, including changes in volume, shape, cell proliferation and growth factor expression.

Do we have detail on what consitutes an ASD DX under these different studies? I've always had a problem with analysis of ASD where the study comes to a conclusion based on self-reported data (food consumption).

There is increasingly stronger evidence that deficiencies of Vitamin D in a pregnant woman may result in abnormalities in a developing brain. Considering that, it shouldn't be surprising if it does affect the development of Autism as well.

As a sample of some of the relatively recent developments involving Vitamin D and neuroembryology, even if not about Autism read on.





This is apparently a preliminary version of a report on some research on the effects of Vitamin D on brain development:

A new study by researchers finds a striking connection between schizophrenia and autism.

“If we hadn’t known that these were two different diseases, and had put all the mutations into a single analysis, it would have come up with very similar networks,” said Dennis Vitkup, Ph.D., associate professor at Columbia University Medical Center.

“It shows how closely the autism and schizophrenia genetic networks are intertwined,” he added.

The study provides new insight into the molecular causes of schizophrenia. It also suggests that mutations associated with schizophrenia, autism, and probably many other psychiatric disorders, most likely come together in certain molecular processes.

Thanks. That's genetics for you.

I think there is a stronger case for crossbreeding than just a common ancestor, but it will probably go back and forth with studies until they come to a conclusion. As it should, as long as it leads to more information and not just the dismissal of a hypothesis for no reason. That recent study didn't take into account the auto-immune stuff either (neanderthal remains with rheumatism etc) or why Homo sapiens would react so badly when they have the HLA alleles found in Neanderthals.

Yes, if they can prove that, it's a really strong case for autism being linked to neanderthal genes.

Off again

Neanderthals first. The initial finding that suggested interbreeding was that Europeans and Asians share a small set of features with the Neanderthal genome that are absent in present-day Africans. This could easily be explained by the first modern humans mating with the Neanderthals they found in the Middle East after exiting Africa and before they spread through Europe and Asia.

But, as the authors of the PNAS paper point out, this model treats all of Africa as a single, giant pool of genes. We know that most populations that cover a large piece of geography aren't like that. Instead, they contain what's technically termed "structure"—different populations may be more or less geographically isolated, and the ones at the extreme ends of the range won't directly exchange genetic variants very often. So, in the case of Africa, you might expect that a population in Ethiopia would have some variants that don't show up at all in a South African population, simply because they're relatively isolated.

The paper raises the possibility, recognized in the original Neanderthal genome work, that the pre-modern African population was structured. So, the group that gave rise to Neanderthals could have a genetic signature that was rare elsewhere in Africa. And, if that same population gave rise to the modern humans that left Africa, it could leave them with that same genetic signature. Thus, Neanderthals and non-Africans would end up looking more similar than we'd otherwise expect.

The authors build a model that incorporates a structure into African populations, with different pools arranged north-to-south, and each pool only allowed to breed with its nearest neighbors. They then modeled the Neanderthals splitting off, and a later population of modern humans migrating out of Africa. Their model produced some results that were completely consistent with the Neanderthal genome data, leading them to caution that we shouldn't be too hasty about concluding there was interbreeding.

On again

With that, we can turn to the preprint that was placed on the arXiv on Friday. In it, some of the people involved in the Neanderthal genome work try to clarify when the shared human/Neanderthal sequences appeared in the human genome. To do that, they look at the shared genetic variants in more detail.

When two genetic variants are close together on a chromosome, they'll tend to be inherited together. Thus, if you got a small chunk of (for example) chromosome five from Neanderthals, all the variants in that section would be the Neanderthal type. Over many generations, however, recombination would start to separate them, leaving the area a mix of Neanderthal and human pieces. Thus, you can look at how mixed up a given genetic area is, and make an estimate of how much time has passed since it was uniform.

In practical terms, you can simply look at variants that have Neanderthal versions, and see how often their nearest neighbors are a Neanderthal version as well. The more often that occurs, the more recent the split must be. The draft paper performed that analysis, and came up with the introduction of Neanderthal DNA occurring between 37,000 and 86,000 years ago. That's after modern humans left Africa, and much, much more recent than the human-Neanderthal split. So, it's clear that the DNA got there through interbreeding, and not a structured population in Africa.

AWwwww you poor baby!
You have a right to rude to others, but others cant be rude to you back!

Exactly WHAT inaccuracy did you point out?

And why is YOUR rude condension "Read some history."acceptable? And mine not?

Columbus did indeed 'discover' america for himself and his sponsers. Nothing that you said contradicted that.
The powers at be in medeaval europe did not know of america.
So FOR THEM - columbus discovered america.

Thus...illustrating my point- that it sometimes pays to risk money on testing a theory. AND further.. it sometimes pays to risk money on testing a theory-even when the theory turns out to be wrong.

Those were my two points.

The fact that vikings (or chinese or phonecians or irish monks) land centuries earlier than columbus doesnt change my point.


READ SOME HISTORY.

The age of exploration and exploitation and settlement of america did not start with those irish monks or phonecians, or even vikings or what have you. It started with columbus. Because widespread european awareness of the new world started with columbus- and not with these earlier adventurers (bold as they have been).

Nitpicking about who landed first doesnt have anything to do with my point.

The fact that you even THINK that it is relevent is mystifying to me.

naturalplastic, I found another article and newer papers says it's on again:

http://arstechnica.com/science/2012/08/ ... -on-again/
(emphasis mine)



There's also this TEDtalk for anyone interested in knowing more
[youtube]http://www.youtube.com/watch?v=kU0ei9ApmsY[/youtube]