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The default position for the human genome is lactose intolerance (why would human mammals ever need to metabolize another mammal's milk?), it's actually a mutation that allows humans to successfully synthesize lactase, the enzyme necessary to metabolize lactose.OK, thanks.
Now the target is smaller.
How do we know a population with, for example, lactose tolerance is caused by successful mutations?
A related question: Are we observing some of the fixation processes on going?
Probably. There are lots of mutations that are not widespread. For example, a relatively recent mutation has been discovered that gives some immunity to HIV. It's possible that this could become fixed in populations at risk of HIV where HIV medication is not, or is only sparsely, available. It's not fixed until it, as the name suggests, is, for all intents and purposes, permanently established in the population, so you only know with hindsight.A related question: Are we observing some of the fixation processes on going?
The default position for the human genome is lactose intolerance (why would human mammals ever need to metabolize another mammal's milk?), it's actually a mutation that allows humans to successfully synthesize lactase, the enzyme necessary to metabolize lactose.
Evolution in action!
http://www.npr.org/sections/thesalt...unit-how-did-humans-develop-lactose-tolerance
"The ability to digest lactose into adulthood (lactase persistence) would have only been useful to humans after the invention of animal husbandry and the domestication of animal species that could provide a consistent source of milk. Hunter-gatherer populations before theNeolithic revolution were overwhelmingly lactose intolerant,[17][18] as are modern hunter-gatherers. Genetic studies suggest that the oldest mutations associated with lactase persistence only reached appreciable levels in human populations in the last 10,000 years.[2][19] Therefore, lactase persistence is often cited as an example of both recent human evolution[20][21] and, as lactase persistence is a genetic trait but animal husbandry a cultural trait, gene-culture coevolution in the mutual human-animal symbiosis initiated with the advent of agriculture.[22] In Northern European populations, the spread of the lactase-persistence allele is most closely correlated with positive selection due to added vitamin D into the diet. Whereas in African populations, where vitamin D deficiency is not as much of an issue, the spread of the allele is most closely correlated with the added calories and nutrition from pastoralism.[2]"How do we know this is true?
There are still many people who are still lactose intolerable. Why?
Probably. There are lots of mutations that are not widespread. For example, a relatively recent mutation has been discovered that gives some immunity to HIV. It's possible that this could become fixed in populations at risk of HIV where HIV medication is not, or is only sparsely, available. It's not fixed until it, as the name suggests, is, for all intents and purposes, permanently established in the population, so you only know with hindsight.
Some people are known to have immunity to HIV and they also have dual copies of a mutated gene that changes a cell receptor protein that HIV needs to infect cells. See The Evolving Genetics of HIV. Occasionally it is that simple.Attribute this kind of special feature to mutation sounds too simple and too convenient. Is there any solid observation that this process is happening?
I don't know the details of those. Probably they'd revert to metabolising the old diet. It depends on what has changed - if they evolved a cellulose breakdown pathway in addition to the existing pathways (a new enzyme perhaps), they might be able to just switch the old system back on (some bacteria have 'switchable' metabolic pathways, depending on what's available). If their existing pathway(s) had been substantially modified, they'd need to repopulate from regressive mutants. Or they might die out - but, in general, the populations are so large and reproduce so rapidly, with a consequently large number of genetic variations, that I'd expect them to persist.Remember those cellulose-eating bacteria? What would happen to those bacteria that eventually became used to the cellulose diet, once the cellular material is taken away and give them back the original food they ate?
A related question: Are we observing some of the fixation processes on going?
Some people are known to have immunity to HIV and they also have dual copies of a mutated gene that changes a cell receptor protein that HIV needs to infect cells. See The Evolving Genetics of HIV. Occasionally it is that simple.
Because the allele codon sequence in that lineage varies from that of the rest of the population in a manner consistent with known forms of mutation. See Evolution of CCR5 Allele & Evidence for a Single Mutation for a brief summary.How can we tell that gene is caused by mutation?
Absolutely we are. Keep in mind that natural selection favors traits that promote reproductive success within a given environment. I bolded that because environmental change is the far greater driver of evolution. And one thing we are observing is evolution of bacteria. We are in an environment where antibiotics are widely used--and very likely overused. We are seeing bacterial populations changing. Those strains that--due to genetic mutations are resistant to current antibiotics--are proliferating. This is micro-evolution, but it is an early step in how new species eventually appear. It is natural selection at work right in front of us.
Yep, and Archeans remain Archeans, and Eukaryotes remain Eukaryotes. No problem with that. A hallmark of evolution is that species necessarily remain within their ancestral rank.In fact, it is a bad, very bad example.
Bacteria evolved through billions of years environmental changes, but are still bacteria.
Amphibians are really just fish that have evolved to be sufficiently different (limbs, living out of water, skin respiration, etc) to justify their own clade or class. Even today there are eleven different genera of fish ('amphibious fish') that demonstrate various stages of that kind of transition (mudskippers, rockskippers, eels, labyrinth fish, etc).So, fishes, might have evolved through the same length of time, should still be fishes, but not becoming amphibians.
Quite likely (depending what you mean by 'seen'). Consider how many generations it would take for even a strongly beneficial mutation to become fixed in even a small human population. The Kuru immunity mutation is a possible candidate, although there may be better ones.I think we have never seen a full mutation-fixation process happened on human.
There's all that talk again. Take it this way, twist it around that way, then turn it under sideways down, and add a few more words until you have convinced yourself you really have a point. The epitome of Atheist speak.
You mean try to explain something to someone who is working so very hard not to understand it? I don't see any reason to bother... If you want to pretend you don't know what complex means
But convince me and maybe some others that you have a legit argument to carry that out.... no.
What is complexity? How to measure it? By what others see as complex. See, most people don't have to measure it...they look at it and go, oh my, that's complex! lol
I'm very serious.I mean you can't be serious with this line of questioning
, but alas, I think you really are.
So easy, at least until one throws common sense out the door because it doesn't work for them at the moment and contrariness does, or so they think.
You seem to need the help, so I'm inclined to make you aware...this pretending stuff your doing here, I've seen a lot of Atheists do it, but you are taking the cake. Since you continue your nonsense, I have to assume you are unable to see most see through you immediately. But do go on if you must, it's interesting if one is in the mood that is, to watch those twists and turns, as someone tries to turn the obvious into something else.
I'm just asking you questions to clarify your very own question.
Don't get so beat up about it and just answer the questions. That is, if you are actually interested in getting answers...
If not, that's fine, but then don't ask the question.
Do you often find yourself reacting this way when others disagree with you?
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