Occam's Aftershave
Posts: 5287
Joined: Feb. 2006
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Whack-a-mole Liar Dave, in his never ending desperate search for some way to discredit ToE, reverts back to the dishonest quote mine tactic
| Quote (Liar Dave @ Nov. 21 2006,21:39) |
Meanwhile ... I have an idea to save the human race from extinction. Let's talk to Planned Parenthood and get them to encourage women to have 40 kids each!
| Quote | NACHMAN AND CROWELL'S PARADOX
M.W. Nachman and S.L. Crowell. 2000. Estimate of the mutation rate per nucleotide in humans. Genetics 156:297-304.
"The human diploid genome ... about 175 new mutations per generation. The high deleterious mutation rate in humans presents a paradox. If mutations interact multiplicatively, the genetic load associated with such high U would be intolerable in species with a low rate of reproduction ... for U=3, the average fitness is reduced to 0.05, or put differently, each female would need to produce 40 offspring for 2 to survive and maintain population size. This assumes that all mortality is due to selection ... so the actual number of offspring required to maintain a constant population size is probably higher." |
Wow! How are we gonna finance college for all those kids??!! |
Dave is citing this paper
Estimate of the Mutation Rate per Nucleotide in Humans
Michael W. Nachmana and Susan L. Crowella
Genetics, Vol. 156, 297-304, September 2000,
Dave cites part of the conclusion, but he somehow 'forgets' to cite the part that explains why there is no 'paradox'
| Quote | | The high deleterious mutation rate in humans presents a paradox. If mutations interact multiplicatively, the genetic load associated with such a high U would be intolerable in species with a low rate of reproduction (MULLER 1950 ; WALLACE 1981 ; CROW 1993 ; KONDRASHOV 1995 ; EYRE-WALKER and KEIGHTLEY 1999 ). The reduction in fitness (i.e., the genetic load) due to deleterious mutations with multiplicative effects is given by 1 - e-U (KIMURA and MORUYAMA 1966 ). For U = 3, the average fitness is reduced to 0.05, or put differently, each female would need to produce 40 offspring for 2 to survive and maintain the population at constant size. This assumes that all mortality is due to selection and so the actual number of offspring required to maintain a constant population size is probably higher. The problem can be mitigated somewhat by soft selection (WALLACE 1991 ) or by selection early in development (e.g., in utero). However, many mutations are unconditionally deleterious and it is improbable that the reproductive potential on average for human females can approach 40 zygotes. This problem can be overcome if most deleterious mutations exhibit synergistic epistasis; that is, if each additional mutation leads to a larger decrease in relative fitness (KONDRASHOV 1995 ; CROW 1997 ; EYRE-WALKER and KEIGHTLEY 1999 ). In the extreme, this gives rise to truncation selection in which all individuals carrying more than a threshold number of mutations are eliminated from the population. While extreme truncation selection seems unrealistic, the results presented here indicate that some form of positive epistasis among deleterious mutations is likely. |
Gee Liar Dave, why did you omit that last part? 
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"CO2 can't re-emit any trapped heat unless all the molecules point the right way"
"All the evidence supports Creation baraminology"
"If it required a mind, planning and design, it isn't materialistic."
"Jews and Christians are Muslims."
- Joke "Sharon" Gallien, world's dumbest YEC.
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