Is Human Intellect Degenerating?
|February 19, 2013||Posted by DLH under Complex Specified Information, Design inference, Evolutionary biology, Genetics, Genomics, Human evolution, Intelligent Design|
Geneticist Gerald R. Crabtree reviews evidence showing genomic mutations are degrading the 2000 to 5000 genes needed for our intellectual and emotional function:
New developments in genetics, anthropology, and neurobiology predict that a very large number of genes underlie our intellectual and emotional abilities, making these abilities genetically surprisingly fragile. . . .
Between 2000 and 5000 genes are needed for intellectual and emotional function. . . .
A recent study of the Online Mendelian Inheritance in Man (OMIM) database, although incomplete, indicates that about half of all human genetic diseases have a neurologic component, , frequently including some aspect of [intellectual deficiency], consistent with the notion that many genes are required for intellectual and emotional function. The reported mutations have been severe alleles, often de novo mutations that reduce fecundity. However, each of these genes will also be subject to dozens if not hundreds of weaker mutations that lead to reduced function, but would not significantly impair fecundity, and hence could accumulate with time. . . .
It is very likely that within 3000 years (~120 generations) we have all sustained two or more mutations harmful to our intellectual or emotional stability. Recent human genome studies revealed that there are, per generation, about 60 new mutations per genome and about 100 hetrozygous mutations per genome that are predicted to produce a loss of function , some of which are likely to affect genes involved in human intellect. . . .
we, as a species, are surprisingly intellectually fragile and perhaps reached a peak 2000-6000 years ago. . . .
Gerald R. Crabtree Our Fragile Intellect. Part 1 Cell Press, TIGS-995
 Marin, O. And Gleeson, J.G. (2011) Function follows form: understanding brain function from a genetic perspective. Curr. Opin. Genet. Dev. 21, 237-239.
 MacArthur, D.G. et al. (2012) A systematic survey of loss-of-function variants in human protein-coding genes. Science 335, 823-828.
It is fascinating to see recognition of substantial cumulative genomic degradation rates. This affirms John C. Sanford’s thesis of accumulating mutations degrading function as described in Genetic Entropy and The Mystery of the Genome. In Mendel’s Accountant, Sanford provides software to quantitatively model this accumulative genomic degradation. See: John C. Sanford and Chase W. Nelson (2012). The Next Step in Understanding Population Dynamics: Comprehensive Numerical Simulation. In: Studies in Population Genetics, M. Carmen Fusté (Ed.), ISBN: 978-953-51-0588-6, InTech.
This raises the questions:
How did this remarkable number of coordinated genes come into being in the face of this rapid rate of genomic degradation?
Is neo-Darwinian evolution possible with such rapid cumulative genomic degradation?
Do these 2000-5000 genes for intellectual and emotional function constitute Complex Specified Information?