Matt Miller

Phylogeography of ninespine sticklebacks (Pungitius pungitius) in North America: glacial refugia and the origins of adaptive traits

The current geographical distribution of the ninespine stickleback (Pungitius pungitius) was shaped in large part by the glaciation events of the Pleistocene epoch (2.6 Mya–10 Kya). Previous efforts to elucidate the phylogeographical history of the ninespine stickleback in North America have focused on a limited set of morphological traits, some of which are likely subject to widespread convergent evolution, thereby potentially obscuring relationships among populations. In this study, we used genetic information from both mitochondrial DNA (mtDNA) sequences and nuclear microsatellite markers to determine the phylogenetic relationships among ninespine stickleback populations. We found that ninespine sticklebacks in North America probably dispersed from at least three glacial refugia—the Mississippi, Bering, and Atlantic refugia—not two as previously thought. However, by applying a molecular clock to our mtDNA data, we found that these three groups diverged long before the most recent glacial period. Our new phylogeny serves as a critical framework for examining the evolution of derived traits in this species, including adaptive phenotypes that evolved multiple times in different lineages. In particular, we inferred that loss of the pelvic (hind fin) skeleton probably evolved independently in populations descended from each of the three putative North American refugia.

Bus Rapid Transit and Economic Development: Case Study of the Eugene-Springfield BRT System

Bus rapid transit (BRT) in the United States is relatively recent. BRT has many promises, one of which is enhancing the economic development prospects of firms locating along the route. Another is to improve overall metropolitan economic performance. In this article, the authors evaluate this issue with respect to one of the nations newest BRT systems that operates in a metropolitan area without rail transit: Eugene-Springfield, Oregon. While the metropolitan area lost jobs between 2004 and 2010, jobs grew within 0.25 miles of BRT stations. Using shift-share analysis, they find that BRT stations are attractive to jobs in several economic sectors. Planning and policy implications are offered along with an outline for future research.

Use of the Real Estate Market to Establish Light Rail Station Catchment Areas

Considerable literature reports the price effects of light rail transit accessibility on residential properties built principally for owner–occupants. Few studies show the relationship between light rail transit and rental apartment building values; those that have done so have evaluated outcomes within narrow bands of distance from light rail transit stations. The present study closes some of this gap in the research. The association between TRAX, the light rail system operated by the Utah Transit Authority serving Salt Lake County, Utah, and the value of rental apartment buildings in bands a distance from light rail stations of 0.25 mi out to 1.5 mi was estimated. When structural, neighborhood, and location characteristics were controlled for, a positive relationship between TRAX station proximity and rental apartment building values was found to 1.25 mi but not beyond. The implications of these findings are offered.

A Val85Met Mutation in Melanocortin-1 Receptor Is Associated with Reductions in Eumelanic Pigmentation and Cell Surface Expression in Domestic Rock Pigeons (Columba livia)

Variation in the melanocortin-1 receptor (Mc1r) is associated with pigmentation diversity in wild and domesticated populations of vertebrates, including several species of birds. Among domestic bird species, pigmentation variation in the rock pigeon ( Columba livia ) is particularly diverse. To determine the potential contribution of Mc1r variants to pigment diversity in pigeons, we sequenced Mc1r in a wide range of pigeon breeds and identified several single nucleotide polymorphisms, including a variant that codes for an amino acid substitution (Val85Met). In contrast to the association between Val85Met and eumelanism in other avian species, this change was associated with pheomelanism in pigeons. In vitro cAMP accumulation and protein expression assays revealed that Val85Met leads to decreased receptor function and reduced cell surface expression of the mutant protein. The reduced in vitro function is consistent with the observed association with reduced eumelanic pigmentation. Comparative genetic and cellular studies provide important insights about the range of mechanisms underlying diversity among vertebrates, including different phenotypic associations with similar mutations in different species.