I suppose that some of you have seen the probability statistic used to point out the fundamental impossibility of life emerging from some kind of primordial soup. Well, this fundamental impossibility is seen at every major transition including the human brain. I don't mean to dump the truck but there are some fundamental things that have to be understood. The most important one is the role of mutations considered the only mechanism for evolution. In order for a genetic mutation to be expressed in the offspring there has to be a germ cell mutation. In order for this to happen in such a way as to grow and develop the human brain there would have to be thousands of mutations.
"The genomic mutation rate is a fundamental evolutionary parameter of any population, determining the rate of influx of new deleterious and beneficial alleles. Because most mutations are likely to be harmful to fitness, DNA repair and proofreading systems have probably evolved so as to minimize rates of mutation"
This is bacteria, it is mutations in bacteria that are the most often cited example of beneficial mutations. Extreme environments don't increase mutation rates since overall fittness declines when this happens. One cause of mutations in bacteria is an arrest of growth due to a lack of resources.
"Because almost all mutations are deleterious to fitness, absolute measures of mean fitness in the replicate populations decrease over time"
EVOLUTION: ON STATIONARY PHASE MUTATION RATES
Here are some examples of the
effects of germline mutations:
Nonsense mutations like cystic fibrosis (over 1000 mutations) when compared to sickle-cell disease (a single mutation) show the dangers of increased mutation rate. For the human brain to have evolved the way it is said to have would have required thousand of mutations.
Indels (insertions and deletions) like Fragile X Syndrome and Huntington's Disease have devastating consequences to the gene because translation of the gene is "frameshifted". This is the result of extra base pairs either being added or deleted, I have yet to see a beneficial effect as the result of on of these mutations.
Duplications occure during meiosis when genes are duplicated, the result is that one family in four generations with this mutation suffered from high blood pressure and were prone early heart attack and stroke. However, it can also result in speciation and if you are paying attention, this may have signifigance for evolution.
Translocations create a break within the gene destroying its function. One example of this kind of mutation is leukemic cells ( chronic myelogenous leukemia).
"It has been estimated that in humans and other mammals, uncorrected errors (= mutations) occur at the rate of about 1 in every 50 million (5 x 107) nucleotides added to the chain."
Mutations
Now let's apply this to human evolution from our supposed most recent common ancestor. The brain size has to grow from 430cc to well over 700cc. Here is an idea of the level of mutations that would be nessacary, this is based on comparisons of the chimpanzee and human genome:
"From a genetic point of view, some scientists thought that human evolution might be a recapitulation of the typical molecular evolutionary process, he said. For example, the evolution of the larger brain might be due to the same processes that led to the evolution of a larger antler or a longer tusk. It's just a particular feature that is exaggerated in the human species.
"We've proven that there is a big distinction.
Human evolution is, in fact, a privileged process because it involves a large number of mutations in a large number of genes," Lahn said. "To accomplish so much in so little evolutionary time a few tens of millions of years requires a selective process that is perhaps categorically different from the typical processes of acquiring new biological traits."
Humans 'privilage' evolutionary lineage
We have been told that only 1.5% of our genes are different from that of our chimpanzee relatives. This is exceedingly deceptive since it does not give you any idea just how vast the distance is and the enourmous amount of change that would be needed.
"By comparing the whole sequence with the human counterpart, chromosome 21, we found that 1.44% of the chromosome consists of single-base substitutions in addition to nearly 68,000 insertions or deletions...
Conclusion
This study shows a chromosome-wide comparison between human and chimpanzee based on high-quality sequences, and provides the first integrated picture of genetic changes during human evolution. The data presented here suggest that the biological consequences due to the genetic differences are much more complicated than previously speculated. We hope that our work offers a framework for the design of future studies to examine differences between the two species."
DNA sequence and comparative analysis of chimpanzee chromosome 22
Now I ask you, what are the odds over 68,000 insertions and deletions resulting the the beneficial effects without harmfull ones listed above? I am still not quite ready to form some kind of a mathmatical model to calculate this for one reason. You can't even get the Darwinian to admitt that germ cell mutations the effect the brain are allways harmfull when observed in natural science. Don't take my word for it, type germ cell mutations and the human brain and you will find all the examples of harmfull effects you could ever want.
I found this and I will wade through it the best I can and get back with what I come up with:
"We now consider in more detail the assumptions behind the analysis made in the article The Mutation Problem. The calculations made in that article assume the standard model of population genetics in which the effects of various harmful mutations on fitness are independent. We now consider whether relaxing this assumption can permit populations to endure a larger number of mutations and thereby remove the difficulty from the theory of evolution."
Effects of Redundancy on Mutation Rates
Gregory Mendel was a creationist who formed the laws of inheritance that have become the cornerstone of modern genetics. It truely amazes me that the work of a creationist my well be the basis for the ultimate demise of Darwinian natural selection.
Grace and peace,
Mark
