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Ne1 mezzo del cammin di nostra vita mi ritrovai per una selva oscura, che la diritta via era smarrita. Ahi quanto a dir qual era 2 cosa dura questa selvu selvaggia ed aspra e forte, che ne1 pensier rinnova la paura. DANTE PREFACE This book has grown, or better, exploded out of the Jesup Lectures that I gave at Columbia in 1969. Previous lecturers, in their(More)
An adaptationist programme has dominated evolutionary thought in England and the United States during the past 40 years. It is based on faith in the power of natural selection as an optimizing agent. It proceeds by breaking an oragnism into unitary 'traits' and proposing an adaptive story for each considered separately. Trade-offs among competing selective(More)
The variation in gene frequency among populations or between generations within a population is a result of breeding structure and selection. But breeding structure should affect all loci and alleles in the same way. If there is significant heterogeneity between loci in their apparent inbreeding coefficients F=s(p) (2)/p(1-p), this heterogeneity may be(More)
HILE the theory of the genetic changes in a population due to selection is quite well understood for single loci, our theory for multiple-gene characters is in a rudimentary stage. Most of the formulations for multiple-gene characters are simply extensions of single-locus models, extensions which ignore the problem of linkage. There are, however, a few(More)
Robustness is the invariance of phenotypes in the face of perturbation. The robustness of phenotypes appears at various levels of biological organization, including gene expression, protein folding, metabolic flux, physiological homeostasis, development, and even organismal fitness. The mechanisms underlying robustness are diverse, ranging from(More)
Various measures have been proposed for characterizing the statistical association that arises between alleles at different loci. Hedrick has compared these measures with the standardized measure D' proposed by Lewontin on the grounds that this latter measure is independent of allele frequency. Although D' has the same range for all allelic frequencies, in(More)
If a population is growing in a randomly varying environment, such that the finite rate of increase per generation is a random variable with no serial autocorrelation, the logarithm of population size at any time t is normally distributed. Even though the expectation of population size may grow infinitely large with time, the probability of extinction may(More)
By using both numerical and analytical approaches, we have shown that heterosis alone is not a mechanism for maintaining many alleles segregating at a locus. Even when all heterozygous are more fit than all homozygotes, the proportion of fitness arrays that will lead to a stable, feasible equilibrium of more than 6 or 7 alleles is vanishingly small. More(More)