Phylogeography of Middle American gophersnakes: Mixed responses to biogeographical barriers across the Mexican Transition Zone.

Aim We used inferences of phylogeographical structure and estimates of divergence times for three species of gophersnakes (Colubridae: Pituophis) distributed across the Mexican Transition Zone (MTZ) to evaluate the postulated association of three Neogene geological events (marine seaway inundation of the Isthmus of Tehuantepec, formation of the Transvolcanic Belt across central Mexico, and secondary uplifting of the Sierra Madre Occidental) and of Pleistocene climate change with inter- and intraspecific diversification. Location Mexico, Guatemala, and the western United States. Methods We combined range-wide sampling (67 individuals representing three putative species distributed across northern Middle America and western North America) and phylogenetic analyses of 1637base pairs of mitochondrial DNA to estimate genealogical relationships and divergence times. The hypothesized concordance of inferred gene trees with geological histories was assessed using topology tests. Results We identified three major lineages of Middle American gophersnakes, and strong phylogeographical structure within each lineage. Gene trees were statistically congruent with hypothesized geological histories for two of the three postulated geological events. Estimated divergence dates and the geographical distribution of genetic variation further support mixed responses to these geological events. Considerable phylogeographical structure appears to have been generated during the Pleistocene. Main conclusions Phylogenetic and phylogeographical structure in gophersnakes distributed across northern Middle America and western North America highlights the influence of both Neogene vicariance events and Pleistocene climate change in shaping genetic diversity in this region. Despite the presence of two major geographical barriers in southern Mexico, extreme geological and environmental heterogeneity in this area may have differentially structured genetic diversity in highland taxa. To the north, co-distributed taxa may display a more predictable pattern of diversification across the warm desert regions. Future studies should incorporate nuclear data to disentangle inferred lineage boundaries and further elucidate patterns of mitochondrial introgression. © 2011 Blackwell Publishing Ltd

Manufacturing In Decline? A Matter Of Definition

This paper offers a new approach to the definition of manufacturing activities, placing them in a broader framework to capture the dynamics of manufacturing in the economy. After discussing why in many cases it may bc appropriate to consider producer services and tnanttfacturing industries together, the paper analyzes the development of manufacturing and producer service industries in the United States. We examine the factors leading to the growth of producer services, concluding that unbundling, the shift of some activities (such as legal, accounting, and data processing services) from manufacturing to producer services industries, is an important explanation for this growth. Finally, we discuss the relationship between manufacturing and producer services. Our analysis, based on a broader definition of manufacturing, shows that over the last two decades the U.S. manufacturing base has declined only slightly rather than radically as suggested in many studies.Manufacturing, Producer services, U. S. economy JEL Classification: L0, L6,

Phylogeographic information systems: putting the geography into phylogeography

Phylogeography is concerned with the observation, description and analysis of the spatial distribution of genotypes and the inference of historical scenarios. In the past, the discipline has concentrated on the historical 'phylo-' component through the utilization of phylogenetic analyses. In contrast, the spatial '-geographic' component is not a prominent feature of many existing phylogenetic approaches and has often been dealt with in a relatively naive fashion. Recently, there has been a resurgence of interest in the importance of geography in evolutionary biology. Thus, we believe that it is time to assess how geographic information is currently handled and incorporated into phylogeographical analysis. Geographical information systems (GISs) are computer systems that facilitate the integration and interrelation of different geographically referenced data sets; however, so far they have been little utilized by the phylogeographical community to manage, analyse and disseminate phylogeographical data. However, the growth in individual studies and the resurgence of interest in the geographical components of genetic pattern and biodiversity should stimulate further uptake. Some advantages of GIS are the integration of disparate data sets via georeferencing, dynamic data base design and update, visualization tools and data mining. An important step in linking GIS to existing phylogeographical and historical biogeographical analysis software and the dissemination of spatial phylogenies will be the establishment of 'GeoPhylo' data standards. We hope that this paper will further stimulate the resurgence of geography as an equal partner in the symbiosis that is phylogeography as well as advertise some benefits that can be obtained from the application of GIS practices and technologies.</p