My wife breast-fed three babies. Nary a molecule of formula ever passed their lips. All three of them developed asthma.

I did not saying that breastfeeding would result in asthma. I was also purely breastfed.

I said overly sterile environments have been linked to higher incidences of asthma. And I thought that it was interesting that my parents wore surgical masks for the first few months of my life and would not anyone in the house to see me. And I developed asthma.

I was responding to the post about keeping one's baby away from public places and not allowing others to hold him/her.

I am a huge advocate of breastfeeding. And certainly it will help one's baby build a better immune system.

-J

I may be slightly confused, but you're a total space cadet.
I'm really sure that we are going to evolve to be volcano resistant.
You seem pretty smart though, so explain in a 100 words or less why people who have antibodies for HIV go on to develope AIDS.

May I? Retroviri work by subverting the immune system itself to reproduce. The immune system is required to attack itself in order to destroy the viri. Resistance is another matter.

And only 27 words.

Bloveld, I know you are new to the forum, but we don't call each other by names here. One gets banned.

The last time I looked there were about 1500 named diseases and 500 cures. Clearly we do not control our environment. Continued evolution for human's is simply a fact. If one misunderstands evolution to be purposive or progressive rather than branching and adaptive it could, I suppose, give rise to a mistaken belief that if has ceased for humans. Clearly we have arrived at a state of perfection.

Where did she say we would evolve to be volcano resistant?

JPaleo, I totally agree with you that an overly sterile environment can be harmful. i meant to say that my SIL was using her avoidance of germs as a way to keep her child safely wrongly. sorry if I was unclear in what i wrote. i think it is pretty universally agreed that children need to be exposed to germs.

in response to the asthma sufferer whose mother did breastfeed. breast-feeding is not magic. it cannot cure something that is genetically or environmentally fated. some people have the genetics or environment that will force them to have asthma, for example, living in a house with significant mold, and others have an initial exposure to something during infancy that when NOT given assistance by the mother's antibodies, can result in illness. it doesn't mean we can avoid all illness or disease by breastfeeding, just that we can avoid some.

first off, volcanoes were included in a long list of things that we are not able to control in the environment. completely unrelated to the question of evolution. my point in that paragraph is that you are entirely wrong about whether or not we can control our environment. the next paragraph covers your argument on evolution.

second, i think the poster above did a nice job of responding to your question about HIV, but I will go ahead and answer it too since you asked me directly.

HIV infects specifically T-cells in your body. T-cells are part of your immune system. What this means is that when HIV has infected your T-cells, your body will kill a significant portion of them as these anti-HIV antibodies bind to them. This reduces the ability of your immune system to respond to OTHER infections, which is the definition of AIDS (acquired immune deficiency syndrome). This is why antibodies to HIV do not help a person avoid AIDS.

Absolutely. My dad is a retired emergency room physician and last summer when we were visiting him, I offhandedly apologized for all the scrapes and cuts my girls had managed to accrue over the past week before we visited. He just chuckled and said, "that just means they're healthy". I replied..."well..yes, they're outside playing a lot and getting excercise along with those scrapes". He shook his head and said, "No, that's not what I meant. Those little nicks and scrapes and minor infections help challenge their immune system and keep it healthy and a healthy immune system means a healthy child."

AIDS and a genetic/evolutionary twist,

They have discovered that people who survived the Black Plague developed a resistant gene and then passed this gene on to their descendents. People having this gene will not get AIDS. They can bombard their blood with the AIDS virus and the virus cannot survive.

Well its debatable whether HIV even exists. Even so I do take steps to avoid it, as do millions of others. Thus that enviroment is controlled. If a natural immunity to HIV exists in some people it is something that has been around for thousands of years. I certainly dont see AIDS as an enviromental pressure that will cause genetic change in humans.
I do realise that a natural disaster could occur at any time, and if it was sweeping enough, and if any of us survived, there would be a period of adaptation. But that pressure does not currently exist.
As I see it, the human race is getting less intelligent and unhealthier. That is in general, as some genius will always pop up somewhere.
There are 2 things which I can think of which may cause adaptation. But they are not currently serious enough to cause us to change.
1. The hole in the ozone layer.
2. Changing composition of the atmosphere.

Steve

If there is a natural immunity to developing AIDS-we have no idea how long it has been in our genome. Mutations are random and mostly due to radiation. Once a mutation pops up, then if it is helpful in surviving a particular environment, it will be selected for. Most mutations are either neutral or deleterious. From what I can gather, there are people who have HIV that NEVER develops into AIDS. This will be a selection event in areas that don't have modern medicine-so we can very well see genetics shifts in those populations.

Actually they have traced the immunity to AIDS back to the Black Plague outbreak. They have traced it through DNA back and forward to specific families and village populations.

There was a large study done on this and they are testing blood of the participants for antibodies in the blood for medical application.

This was definitely a mutation caused by the Black Plague that showed up in its survivors' genes and was passed on to descendants.

We know there are people that never get certain conditions or can be carriers of disease but never get sick. These are mutations.

Mutations are adaptations. Adaptations carried through multiple generations that become widespread comprise evolution.

They may have traced the mutation as far as the Plague-but that does not tell us when it originally appeared in the genome-especially since the Plague caused a bottleneck which can underestimate the time a mutation appears. The plague did not cause the mutation, as far as I know-it was already present.

Edited to add: Mutations ARE NOT adaptations. Mutations are just mutations.

Sorry, I will clarify.
They traced it back to it's appearance in an individual after the plague. They traced it back beyond that, to the parents and other lines descended from those parents where it did not appear. Thus they proved the mutation in the gene was caused by the Black Plague. Further, there was not one Black Plague outbreak and they did the same research on survivors descendants for those also.

They stated their luck was in because the stories and breadth of the DNA links were documentable and easily verifiable, the family/village populations were documented, stable and settled until and past the 20th century.

The definition that I found is that evolution is "the adaptation of mutations".

http://info.bio.cmu.edu/Courses/034...vo/mutation.htm
Mutations are naturally occurring events in any genome. They are one of many mechanisms that bring change into genome of a species. When the characteristic brought about by the mutation, allow the organism to better fit the changing environment, the organism survives and passes down the trait through reproduction. Thus, species as a whole evolve.

http://www.sciencedaily.com/release...40212083108.htm

Genetic Mutation Protects Against Both HIV And Plague? Not So, Say Scientists At Scripps Research

La Jolla, CA, February 11, 2004 -- A group of scientists at The Scripps Research Institute have provided strong evidence that a popular hypothesis concerning the origins of a genetic mutation common among Caucasians of Northern European descent that protects against human immunodeficiency virus (HIV) is wrong.

The hypothesis suggests that the mutation conferred resistance against bubonic plague in the Middle Ages, much as it does against HIV today. This idea was based on the fact that the mutation first appeared around the same time that the "Black Death" plague epidemic killed a third of Europe's population in the years 1346–1352. Since HIV was not present in Europe at this time, individuals with the mutation must have been protected against some other disease.

In a brief communication to be published this week in the journal Nature, Scripps Research Immunology Professor Donald Mosier and his colleagues show this hypothesis to be incorrect.

Mosier performed studies that demonstrate that the mutation does not protect against plague infection in mouse models and that it is unlikely to have offered any protection against the plague in humans during the Middle Ages.

An Important Receptor

The mutation in question is in the C–C chemokine receptor 5 gene, which makes the human receptor protein called CCR5. CCR5 is a seven trans-membrane spanning protein of 332 amino acids that inserts into the cell membranes of human CD4+ T helper cells. HIV particles use CCR5 to gain entry into CD4+ T cells.

The CCR5 Ä32 mutation—a deletion of 32 bases of DNA from the CCR5 gene—was first identified in 1996 in individuals who seemed to be protected from infection with HIV despite having had multiple high-risk exposures to the virus.

The resistant individuals all had the 32-base pair mutation in their CCR5 genes, and that left them with CD4+ T cells with no CCR5 receptors, conferring resistance to HIV infection. Later data showed that individuals

who were heterozygous for the mutation had lower CCR5 expression levels, less cell-to-cell infection, and brighter clinical prognoses.

In order to test the HIV–plague hypothesis, an attenuated, non-transmissible form of Yersinia pestis, the bacterial cause of plague, was tested on mice both with and without the CCR5 Ä32 mutation. There was no difference in susceptibility between the two groups, says Mosier.

The possibility still exists, says Mosier, that the CCR5 Ä32 mutation arose due to the influence of some other disease that was prevalent in the Middle Ages, such as smallpox. Mosier plans to address this possibility next.

The brief communication, "CCR5 mutation and protection against plague" was authored by Joan Mecsas, Greg Franklin,William A. Kuziel, Robert R. Brubaker, Stanley Falkow, and Donald E. Mosier and appears in the February 12, 2004 issue of the journal Nature.

This work was supported by the National Institutes of Health.

About The Scripps Research Institute

The Scripps Research Institute in La Jolla, California, is one of the world's largest, private, non-profit biomedical research organizations. It stands at the forefront of basic biomedical science that seeks to comprehend the most fundamental processes of life. Scripps Research is internationally recognized for its research into immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune diseases, cardiovascular diseases and synthetic vaccine development.

Editor's Note: The original news release can be found here.