In 1957, the renowned evolutionary geneticist J.B.S. Haldane published a : problem that eventually bore his name "Haldane's Dilemma." He saw that : reproductive capacity is limited, and this puts a limit on the speed of : evolution. So far, so good. The absolute maximum rate of evolution is limited by a.) how often mutations occur (supplying new genetic variation) and b.) how fast beneficial mutations sweep to fixation (go from a frequency of 1/N (in haploids, 1/2N in diploids -- where N is population size) to one.) Reproductive capacity limits the rate of how fast an allele sweeps to fixation (under soft selection). This rate is often called s, the selective coefficient, in population genetics. (Kimura gives the rate of evolution as k = 4*Ne*s*v -- where k is nucleotide substitutions, Ne is effective population size, s is the selective coefficient and v is the rate of advantageous mutations (obviously a fraction of the total mutation rate.) : He showed that in species with low reproductive capacity : (such as higher vertebrates, mammals and man), the long-term average : beneficial substitution rate cannot be faster than one substitution per : 300 generations. He showed that under hard selection, this was the limit. :These substitutions are single nucleotides. These substitution are alleles; they may or may not be single nucletides. This is trivial, however (at least for our discussion). : 1,667 beneficial nucleotide substitutions amounts to about 50 millionths : of one percent of the human genome. And that is *before* making several : deductions, such as the 90% reduction due to the 90% of the time spent in : stasis, according to Gould. Gould posits that, on average, species spend 90% of their time in stasis. Also, he thinks most change is clustered near speciation time. Humans have recently speciated from chimps, and the fossil record records mostly change from the human/chimp ancestor on. It could very well be that most of the time from the chimp/human ancestor until now we were changing, not in stasis. Gould does not say (and his model does not predict) that during any given time frame species are in stasis 90% of the time -- the amount of time they are in stasis should vary depending on how far they are away from speciation. (I should state that this is Gould and Eldrege's _model_; I'm not saying this is how evolution really works.) : Is a maximum of 1,667 beneficial nucleotides : enough to make a sapien out of a simian? This number (best expressed in allelic substitutions, not nuclotide substitutions) may be greater under soft selection, something you have consistently ignored. In addition, you have never defended your assertion that 1667 substitutions is too few. As I've said, and you've deleted, before: a.) humans are the result of the alteration of already existing developmental patterns in apes (at least, that is the current model) and b.) changes in regulatory sequences can effect the expression of many genes. The case that small amounts of change in regulatory sequences can cause large changes in morphology is rather common in the literature. : This is commonplace in textbooks on evolutionary genetics. Here is an : additional brief sampling of modern books, where everything is absent. ^^^^^^^^^^ : Molecular Evolutionary Genetics, Nei, 1987 Read the title Walt, its a _molecular_ book, not population genetics. : Genetics of Populations, Hedrick, 1983 (***Mentions soft selection, but : doesn't tie it in as essential.) ^^^^^^^^^^^^^^^^^^^^^^^ : Population Genetics and Molecular Evolution, edited by Ohta and Aoki, : 1985 (***Mentions truncation selection in one paragraph, but doesn't ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ : define it or tie it in as essential.) : Genetics, Paleontology, and Macroevolution, Levinton, 1988 (***Mentions : truncation in one paragraph, but doesn't tie it in as essential.) ^^^^^^^^^^ Uh Walt, if they mention soft and truncation selection, you can't really say _everything_ is absent now can you? This leaves us with three: : Rates of Evolution, edited by Campbell and Day, 1987 (About half this : book is evolutionary genetics, but the stated topic of the book makes the : omission of both the Haldane problem and solution especially notable.) : Theoretical Population Genetics, Gale, 1990 : Population and Evolutionary Genetics: A Primer, Ayala, 1982 OK, shame on them for leaving out an interesting mathematical model. But, when books like Lewontin's "The Genetic Basis of Evolutionary Change" and others discuss it in detail; does the same information need to be rehashed everywhere? Don't you think some (most) books are going to focus on a topic narrower than "everything under the sun about evolution"? END*************************************************************************