Also, favorable mutations are propagated more quickly in nuclear DNA due to the advantages of sexual reproduction. If one defines mutation rate as changes in the genome over time, it might change the answer.
Well regardless of if you fall into the neutralist or selectionist camp, nearly everyone who studies molecular evolution agrees that very, very few mutatations are advantagous- they are deleterious or at best neutral. So theory predicts that sex should not speed up rates of evolution, at least in this manner. (Though I'm not aware of a study comparing rates in sexual and asxual organisms of the same species - but it would be interesting.)
And again, the mutation rates which have been measured are per nucleotide per year at silent sites.
First, a number. For synonymous subsitutions (muations where a nucleotide changes but this change does not affect the protein product due to degeneracy), the rate in mammals has been estimated at 5.7 x 10^-8 subsitutions per site per year. Thats a pretty small number: most of yours and mine and everyone elses mtDNA is identical.
As I read it, what you are asking about is what is known as a molecular clock. The idea of a molecular clock is using a macromolecule (DNA or protein) to date the time when an evolutionary event occured (like the most recent common ancestor of all humans today- mitochondiral eve.) In short, if we compare DNA sequences, we can find out how many sites they differ at. Then, if we know the rate of substiutions, we can figure out how long it has been since we all diverged.
I say if because its not at all clear that rates of molecular evolution are constant between different groups. It seems that things like generation time, metabolic rate, body temperature and maybe even population size effect rates of molecular evolution. So our (human) rate of molecular evolution might be an order of magnitude different from the number I already gave. And the precise value of this rate will determine the value given for the age of Mitochondrial Eve.
To nitpick for a moment- mtDNA actually mutates faster than nuclear DNA: most molecular evolution studies come up with values of 5 to 10 times faster. There are probably several reasons for this.
One of the major factors is that oxygen radicals (which are potent mutagens) are produced in high quantities in the mitochondira as ATP is produced to power the cell. Mitochondira also seem to lack some of the error checking mechanisms in DNA replication that nuclear DNA has avaliable to it.
The usually very reliable MacOS Rumors quotes soruces as saying, probably not at Paris- probably not until November. We can play with rumors all we want, but none of us really know a thing...
(Besides, Apple has to ramp up production of iBooks and the new PowerMac- where are they going to make iMacs?)
The distinction you make is important, and I think it applies to biotech just as well. People who do the science of biology make testable hypotheses about the world and then come up with experiments which can differnetiate between these competing hypotheses. Just like computer scientists who could never write a line of code, the people can make strides without ever picking up a pipette.
Like the people how write HTML or sysadmin, biotech requires a lot of people who can culture cells, sequence DNA, make recombinant plasmids and purify proteins. Many of these people will be extrodanary technicians, just like people who can run a complicated network. But neither of them are asked to, (or have any facility in) making any kind of breakthoughs...
The thing to keep in mind is that Apple isn't expecting that kind of huge volunteer response. Much like Mozilla, they fully expect to continue developing their OS with their own folks. If the get some bug fixes or new ideas, that is wonderful for them- but Apple has its own goals which are undoubtably different from many of our own, and Apple will make sure to focus their efforts there.
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And again, the mutation rates which have been measured are per nucleotide per year at silent sites.
As I read it, what you are asking about is what is known as a molecular clock. The idea of a molecular clock is using a macromolecule (DNA or protein) to date the time when an evolutionary event occured (like the most recent common ancestor of all humans today- mitochondiral eve.) In short, if we compare DNA sequences, we can find out how many sites they differ at. Then, if we know the rate of substiutions, we can figure out how long it has been since we all diverged.
I say if because its not at all clear that rates of molecular evolution are constant between different groups. It seems that things like generation time, metabolic rate, body temperature and maybe even population size effect rates of molecular evolution. So our (human) rate of molecular evolution might be an order of magnitude different from the number I already gave. And the precise value of this rate will determine the value given for the age of Mitochondrial Eve.
One of the major factors is that oxygen radicals (which are potent mutagens) are produced in high quantities in the mitochondira as ATP is produced to power the cell. Mitochondira also seem to lack some of the error checking mechanisms in DNA replication that nuclear DNA has avaliable to it.
(Besides, Apple has to ramp up production of iBooks and the new PowerMac- where are they going to make iMacs?)
The distinction you make is important, and I think it applies to biotech just as well. People who do the science of biology make testable hypotheses about the world and then come up with experiments which can differnetiate between these competing hypotheses. Just like computer scientists who could never write a line of code, the people can make strides without ever picking up a pipette.
Like the people how write HTML or sysadmin, biotech requires a lot of people who can culture cells, sequence DNA, make recombinant plasmids and purify proteins. Many of these people will be extrodanary technicians, just like people who can run a complicated network. But neither of them are asked to, (or have any facility in) making any kind of breakthoughs...
Check out http://www.MacKiDo.com/Hardware/USB20.html for some good background
The thing to keep in mind is that Apple isn't expecting that kind of huge volunteer response. Much like Mozilla, they fully expect to continue developing their OS with their own folks. If the get some bug fixes or new ideas, that is wonderful for them- but Apple has its own goals which are undoubtably different from many of our own, and Apple will make sure to focus their efforts there.