interstate road map of the United States may be helpful in driving cross-country but is of no use in navigating the Freedom Trail in Boston for which a fine-grained local map provides the appropriate resolution. Similarly, phylogenetic summaries capture varying degrees of generalization about the streams and watersheds of heredity that make phylogeny, and a given depiction should be matched to the problem at hand. It has been the thesis of this paper that the “species problem” cannot be properly addressed from a phylogenetic perspective without reference to the fine-focus details of pedigrees and of lineage sorting processes at microevolutionary scales, and that an incorporation of such perspectives can resolve many of the apparent conflicts previously emphasized between the PSC and the BSC. To paraphrase and adapt the quotation from Dobzhansky (1) that opened this paper: population genetics has so profound a bearing on the problem of the mechanisms of speciation that any speciation theory that disregards established population genetic principles is faulty at its source.

We thank the National Science Foundation for continued support of the Avise laboratory.

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Contents (R1-R2)

Genetics and the origin of species: An introduction (1-7)

Origin of Genes (8-13)

Transposable elements as sources of variation in animals and plants (14-21)

Long term trends in the evolution of H(3) HA1 human influenza type A (22-28)

Genes, people, and languages (29-34)

DNA variation at the Sod locus of Drosophila melanogaster: An unfolding story of natural selection (35-39)

Neutral behavior of shared polymorphism (40-44)

Divergent and conserved features in the spatial expression of the Drosophila pseudoobscura esterase-5B gene and the esterase-6 gene of Drosophila melanogaster (45-51)

A demographic approach to selection (52-57)

Phylogenetics and the origin of species (58-65)

Assortative fertilization in Drosophilia (66-70)

Incipient species formation in salamanders of the Ensatina complex (71-77)

Genetics and the origin of bird species (78-85)

Vagaries of the molecular clock (86-93)

Evolution of codon usage bias in Drosophila (94-100)

The evolution of plant nuclear genes (101-108)

Evolution by the birth-and-death process in multigene families of the vertebrate immune system (109-116)