Mouthpieces For Braces

The evolution as a cultural product II

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Not all mutations are disadvantageous, and not all are set
advantageous . As I will use the HapMap, which consists of a list of more than 3 million genetic polymorphisms (SNPs) drawn from the population of Northern Europe, West Africa and East and so on.
When making long chains of DNA from many people consider the frequency of many polymorphisms.
But in this study also studied the SNPs linked to other, so the possibility of selecting alleles increases the frequency of the population.
This gave the impression that a long-range association of SNPs is an imbalance. And you can see that the recombination of DNA are very rare around the SNPs and in particular when one or two SNP alleles are about non-recombinant chromosomes, but other alleles seem to recombine normally. This track is a strong indication that it is selected.
The analysis was based on Yoruba over 3000, 2800 and 2300 European Asian and based on the average percentage of crossing over can tell how quickly they are broken down by recombination and can give an estimated age of the mutations. In Chart 3 shows that the ages represent the time the time from initial mutation established for each allele.
Each point represents the number of different genes and the Y axis is the number. And as you can see there are many of the selected genes that began appearing some 10,000 years ago and less about for 40.000 and these were fewer than 80.000 years ago.
The most interesting is that these curves are well suited for population growth.
The differences between Africans and Europeans are clearly noted. That is because in Africa there is much more diverse than Europe and the populations are older, so the genes are selected in Europe after those in Africa ..
This is because during the Neolithic Africa had a greater population than asia and europe ..
To test the acceleration in the evolution, the researchers took the null hypothesis. This is that there have been no changes.
And that meant that there was a high rate of selection and proved that this was not true and reject the null hypothesis of adaptation and pony, then show that human evolution has accelerated.
If the hypothesis is true should there be a whole lot more selected mutations that reached or are close to reaching the fixing before we see a relatively small number still varies in human populations. And that's exactly what they did and you can see in chart 2.
In the bottom of this chart there is the age distribution of the variants. That would represent a small fraction of the total.
But you can see from the graph that if the rate was constant, the total number had to be very large, and that they were looking for 10 generations of the sites and has 150 of the predicted substitutions in 10 generations or so ½ a year. And therefore
40.000 years ago almost all should be close to fixation in the genome .. This large number
term generally have very small because they tend to polymorphism with alleles tend to a close and eliminate variation. And therefore
diversity across the genome should be a tenth of what is actually observed. And therefore the null hypothesis is disproved.
To know what has been accelerating fast in recent years and if in fact is accelerating compared to those of the ancestors, who come from 12 million years ago, and as we know it will occur at a rate of ½ year should be an amazing number of variations, between us and chimpanzees. But there are only a 40.000 on the amino acid substitutions. Y is therefore 100 times faster than normal in most of human evolution.
This was due mainly to the huge increase in population in recent years.
Many of the selected genes are in defense of pathogens, others are related to metabolism, or even directly with the diet. The example of lactase is a good example in this category.
These mutations usually not noticed in the phenotype of the fossils. And the only way is extract DNA from the bones to see if the new alleles found in them.
In the early months of the year came in a paper by Burger PNAS a sample analysis of the skeletons of the Neolithic in Europe, and in each case there was no allele for lactase into adulthood. Not a
.
now exists in Europe, 90% of the frequency of this allele.
What happened there?.
For this allele in particular have good times and appeared between 6000 and 10000 years, this difference is that the principle was rarely transmitted, but as the population grew and persisted dietary change, that allele became the majority in Europe. Not so in Asia and many parts of Africa ..
One of the most interesting things is that in northern Europe nearly all have, as I said a ratio of 90% but this often decreases when it goes south, in Italy, Spain, and Greece is 60% .
And this accords with the diet they have in those countries, and how the culture of breeding cows was stronger in the north (where there were fewer sources of food in the winter) than in the south where there was greater variety in the winter.
This research is just beginning. And there are many points that still need to investigate. At least the blue eyes. 12000 years ago nobody had blue eyes, as the OCA2 gene had not appeared and now those with blue eyes are 5% more likely to reproduce the black eyes, although this type of eye are brown control yourself. Venezuela

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a good graph of the NYT, I can not put but is very explanatory.

http://www.nytimes.com/imagepages/2007/12/10/science/20071211_EVOL_GRAPHIC.html Also this link is a good reference for this study.

http://www.sciam.com/article.cfm?id=are-human-beings-still-ev

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Thing To Put On Dog's Grave

man as a product of the evolution of culture time

Like most good stories, this one begins with Darwin . He was always interested in hybrids as it seemed it was the best way to see how evolution works. As a fan of the Orchid, so I always had in mind. When you make a hybrid between two species of orchids, the grex (total population of the cross) can go from very small dishes and tall plants and flowers can be really ugly, a plant, won by a FCC (First Certificate class) which only a score (by gender) of plants receive annually from the millions of plants that occur in the world. On average only 0.0001% of the junction (grex) is likely to get that award.
That tells us that the greater number of plants we have, the more likely we are to get an exceptional plant.
That was taken by Marx when I say that the amount could make the quality. The most importate
of a population is the number and frequency of births, to face the changing environment.

For example, in us there is a mutation called focomegalia two, the child is born without arms, but with hands and feet but no legs, is that the hands are on the shoulders and feet on waist. In our current world
this mutation has a very low probability of living, and is not viable. But if we lived in an environment of swamps and shallow, could have an evolutionary advantage to survive, and if there are more like them, could eventually form a species.
In the last century saw Fischer of the magnitude of that fact, and realized that if the population was large, the development would go faster than in small towns. But only when there is a limit of mutations. According
Ficher:

The great contrast entre Abundant and rare species lies in the number of
disponible en individuos Each generation as possible mutants .... The Importance
of the contrast lies with the Extremely rare mutations, in Which the number of new mutations Occurring
Must Increase proportionately to the number of
individuos available.

This has been abundantly demonstrated, at least with pesticides and insects, there comes a point where pesticides will not take effect for insects, since some of them have developed mutant genes that allow you to survive this toxic .
In bacteria, this fact has had dramatic consequences, because we are running out of antibiotics to combat bacterial disease most. When at the beginning when penicillin was developed, the acting almost magical way against all bacteria.
That is because both the bacteria and insects have large populations and their reproduction is very fast, this makes it is possible that an antibiotic can kill 99.9999999999% of the bacteria, but those that survive will have a mutation that permit return to its original population in a short time and that specific antibiotic will not hurt. In insects, the pesticide affects a number of genes that cambairan to cope with the pesticide.
Usually they are not transmitted perfectly, or conflict with other genes. But if it is spread on large areas, the mutations will be selected by the pesticide, to achieve it successful.
That happens in such a billion cockroaches (10 to the 9) but that never happens in her laboratory.
But that was not human speech?

At about going, but had to understand this.
After the explosion of the Toba, the human population was nearly extinct, and only very slowly survivors somehow began to prosper. 50.000 years ago the human population began to grow. And most importantly, began to spread over large areas, covering many different habitat, from ls deserts to mountains and forests to large temperate plains. We have the requirement to accelerate the evolution.
about 11000 years ago to create agriculture, in response to the demise of the Pleistocene megafauna.
Agriculture allowed the population increased exponentially, and I think the first people. In those villages diseases spread quickly.
For example, some epidemics are caused in large populations are cholera, smallpox and malaria, were originally mortal. When the English arrived here, smallpox virtually destroy entire populations. The first explorers of the Mississippi and the Amazon were large settlements that stretched for hundreds of miles, but when other explorers came to these places and these cities had disappeared and no one was there.
in Europe and Asia that had thousands of years living with these diseases were rarely fatal. The same AIDS currently 10% of Europeans have CCR5 gene that makes them immune to this disease through genes that appeared about 4000 years (the average in Africa is similar) that was due to human who had genes that made them immune to these diseases were those who could play.
In Mexico and Peru, where they had large populations, where they could find the genes that made them immune or less affected by these diseases were more who survived, and it is for this reason that the natives of the new world, these diseases are now fatal.
An example of how culture has affected our evolution is the gene to produce lactose, the gene becomes nonfunctional nearly 10 years of age. But due to agriculture and the domestication of Europeans and certain African tribes developed a mutation that allows them to drink milk throughout life (I have it).
What more intention to call on us is the size of the brain. A brain uses about 20% of all our energy, so it is costly, evolution has two limits, the cost and benefits. A smaller brain, it would be more appropriate, but might not have the same functions as our cerbro grew, despite the cost to maintain it, because that for us was the only weapon we had to survive.
But not only is the brain, if not it contains
Nobody knows, for whatever reason some 50,000 years ago man began making art and I think maybe the first gods, but had to be something that happened inside our brains. There was a sudden change in how we processed the information, it is possible that this was the result of a mutation that was beneficial as it spread throughout the population, but if that's the case, although we have the alleles of the previous situation.
A quick way to identify interesting sites of the genome is to identify the SNPs , (single-nucleotide polymorphisms) in fact performed Vader sequence of the genome map using the technique of SNP s that was what made Henry Harpending paleantropologo of laUniversity of Utah in Salt Lake City analyze 270 DNA in the HapMap which is a effort to identify variations in human genes that cause disease. And look for mutations in the alleles that have spread in the population. These SNPs are flaqueados by thousands for more than 10,000 DNA bases identical, that means it is a favorable mutation under the selective pressure must be preserved in the lineage. They found there were more than 1800 genes that had appeared recently, many of which is not known for serving, about 7% of all genes.
And these the majority had emerged in the last 5000 or 7000 years.
what was what happened at that stage? the number of people living in towns increased, the same feeding change radically, and that there was agriculture and the domestication of animals, including chickens. and the exchange of information people are exponentiate tremendously. All these changes also changed us.
was thought that human evolution had been gradual. But this changes everything. To be more explicit to say I like the process. Consider
measure diploid SNP genotypes in locations # 1 and # 5 along a single chromosome of a single individual: Locus

1 - AA Locus
2 - AG Locus
3 - CC
Locus 4 - GT Locus
5 - TT
On the basis that ( unphased) data alone can not tell what the genotype along each chromosome. There are four possibilities (stage):
AACGT
AGCTT

AGCGT
AACTT

AACTT
AGCGT

AGCTT
AACGT

It can be determined experimentally in this order throughout the region. And we can deduce with some accuracy the phase is very likely given enough samples of unrelated individuals of the population. Or given the genotypes of the people involved, you can even make a more precise estimate of the stage that is correct.
That's very strange.

I'll cut it here not very long, but as I have written what I am. I actually came out quite long as well I have some observations about the methods used and the mathematics of the article, which I shall. But basically first explain everything about the discovery, and its possible consequences, and then make my comments on the methods, although I am convinced that there is something very important there, you can discrepacias unmitigated success. I will try as much as possible not to put anything in probability, statistics or stochastic processes, and not to do that, I have to talk more, not to rare equations. Venezuela
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