We describe a map of 1.42 million single nucleotide polymorphisms (SNPs) distributed throughout the human genome, providing an average density on available sequence of one SNP every 1.9 kilobases. These SNPs were primarily discovered by two projects: The SNP Consortium and the analysis of clone overlaps by the International Human Genome Sequencing Consortium. The map integrates all publicly available SNPs with described genes and other genomic features. We estimate that 60,000 SNPs fall within exon (coding and untranslated regions), and 85% of exons are within 5 kb of the nearest SNP. Nucleotide diversity varies greatly across the genome, in a manner broadly consistent with a standard population genetic model of human history. This high-density SNP map provides a public resource for defining haplotype variation across the genome, and should help to identify biomedically important genes for diagnosis and therapy.

Habitat loss and fragmentation due to urbanization are the most pervasive threats to biodiversity in southern California. Loss of habitat and fragmentation can lower migration rates and genetic connectivity among remaining populations of native species, reducing genetic variability and increasing extinction risk. However, it may be difficult to separate the effects of recent anthropogenic fragmentation from the genetic signature of prehistoric fragmentation due to previous natural geological and climatic changes. To address these challenges, we examined the phylogenetic and population genetic structure of a flightless insect endemic to cismontane southern California, Stenopelmatus'mahogani' (Orthoptera: Stenopelmatidae). Analyses of mitochondrial DNA sequence data suggest that diversification across southern California began during the Pleistocene, with most haplotypes currently restricted to a single population. Patterns of genetic divergence correlate with contemporary urbanization, even after correcting for (geographical information system) GIS-based reconstructions of fragmentation during the Pleistocene. Theoretical simulations confirm that contemporary patterns of genetic structure could be produced by recent urban fragmentation using biologically reasonable assumptions about model parameters. Diversity within populations was positively correlated with current fragment size, but not prehistoric fragment size, suggesting that the effects of increased drift following anthropogenic fragmentation are already being seen. Loss of genetic connectivity and diversity can hinder a population's ability to adapt to ecological perturbations commonly associated with urbanization, such as habitat degradation, climatic changes and introduced species. Consequently, our results underscore the importance of preserving and restoring landscape connectivity for long-term persistence of low vagility native species.

The cricket pet food industry in the United States, where as many as 50 million crickets are shipped a week, is a multi-million dollar business that has been devastated by epizootic Acheta domesticus densovirus (AdDNV) outbreaks. Efforts to find an alternative, virus-resistant field cricket species have led to the widespread USA (and European) distribution of a previously unnamed Gryllus species despite existing USA federal regulations to prevent such movement. We analyze and describe this previously unnamed Gryllus and propose additional measures to minimize its potential risk to native fauna and agriculture. Additionally, and more worrisome, is our incidental finding that the naturally widespread African, European, and Asian “black cricket,” G. bimaculatus, is also being sold illegally in southern California pet food stores. We assayed crickets of all five USA and European commercial species for presence of the AdDNV to document extent of the infection—all five species can be infected with the virus but only A. domesticus is killed. Based on its already cosmopolitan distribution, apparent inability to live away from human habitation, and resistance to AdDNV, we suggest that Gryllodes sigillatus is the best-suited replacement cricket for commercial production.

Gryllus field and wood crickets of the United States, mostly west of the Mississippi River, are reviewed and revised. We validate the following 18 Gryllus cricket names: G. armatus, G. assimilis, G. brevicaudus, G. cayensis, G. cohni, G. firmus, G. fultoni, G. integer, G. lineaticeps, G. multipulsator, G. ovisopis, G. pennsylvanicus, G. personatus, G. rubens, G. texensis, G. veletis, G. vernalis, and G. vocalis. We synonymize G. alogus under G. vocalis. We designate a lectotype for G. armatus. We describe the following 17 new Gryllus species: G. chisosensis, G. leei, G. lightfooti, G. longicercus, G. makhosica, G. montis, G. navajo, G. planeta, G. regularis, G. saxatilis, G. sotol, G. staccato, G. thinos, G. transpecos, G. veintinueve, G. veletisoides, and G. vulcanus. We present biology, distribution, and genetic analysis of all taxa and discuss their nearest relatives.