some specific order relative to other isolating mechanisms (i.e., premating or postzygotic) has not been addressed. Negative assortative fertilization should promote outcrossing. Whether or not true self-incompatibility exists in Drosophila or other animals remains to be established, as does the nature of the interplay between negative assortative fertilization and other isolating mechanisms that act before or after fertilization.

Discussions with M.Wolfner and R.Richmond and with my former students S.Pitnick and R.Snook have been especially stimulating during the preparation of this manuscript. Bruce Wallace provided valuable editorial comments on an earlier draft. I also acknowledge the assistance of M. St. Louis, S.Murphy, S.Cleland, and S.Bertram and the support of National Science Foundation Grants INT 94–02161 and DEB 95–10645.

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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)