Lower jaw modularity in the African clawed frog (Xenopus laevis) and fire salamander (Salamandra salamandra gigliolii)

Modularity describes the degree to which the components of complex phenotypes vary semi-autonomously due to developmental, genetic and functional correlations. This is a key feature underlying the potential for evolvability, as it can allow individual components to respond to different selective pressures semi-independently. The vertebrate lower jaw has become a model anatomical system for understanding modularity, but to date most of this work has focused on the mandible of mammals and other amniotes. In contrast, modularity in the mandible of lissamphibians has been less well studied. Here, we used geometric morphometrics to quantify the static (intraspecific) modularity patterns in Xenopus laevis and Salamandra salamandra gigliolii. We tested developmental and functional hypotheses of modularity and demonstrate that both species exhibit significant modularity. Functional modularity was supported in both Xenopus and Salamandra. Allometry has a small yet significant impact on lower jaw shape in both taxa and sex has a significant effect on shape in Xenopus. The high lower jaw modularity in both species observed here, combined with the well-established modularity of the amphibian cranium, suggests that modularity is a ubiquitous feature of the tetrapod head

Phylogenetic interrelationships of the barbets (Aves: Capitonidae) and toucans (Aves: Ramphastidae) based on morphology with comparisons to DNA-DNA hybridization

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73985/1/j.1096-3642.1988.tb01728.x.pd

Similar Genetic Mechanisms Underlie the Parallel Evolution of Floral Phenotypes

The repeated origin of similar phenotypes is invaluable for studying the underlying genetics of adaptive traits; molecular evidence, however, is lacking for most examples of such similarity. The floral morphology of neotropical Malpighiaceae is distinctive and highly conserved, especially with regard to symmetry, and is thought to result from specialization on oil-bee pollinators. We recently demonstrated that CYCLOIDEA2–like genes (CYC2A and CYC2B) are associated with the development of the stereotypical floral zygomorphy that is critical to this plant–pollinator mutualism. Here, we build on this developmental framework to characterize floral symmetry in three clades of Malpighiaceae that have independently lost their oil bee association and experienced parallel shifts in their floral morphology, especially in regard to symmetry. We show that in each case these species exhibit a loss of CYC2B function, and a strikingly similar shift in the expression of CYC2A that is coincident with their shift in floral symmetry. These results indicate that similar floral phenotypes in this large angiosperm clade have evolved via parallel genetic changes from an otherwise highly conserved developmental program

Metabolic power in hurling with respect to position and halves of match-play.

The current investigation compared the metabolic power and energetic characteristics in team sports with respect to positional lines and halves of match-play. Global positioning system (GPS) technology data were collected from 22 elite competitive hurling matches over a 3-season period. A total of 250 complete match-files were recorded with players split into positional groups of full-back; half-back; midfield; half-forward; full-forward. Raw GPS data were exported into a customized spreadsheet that provided estimations of metabolic power and speed variables across match-play events (average metabolic power [Pmet], high metabolic load distance [HMLD], total distance, relative distance, high-speed distance, maximal speed, accelerations, and deceleration). Pmet, HMLD, total, relative and high-speed distance were 8.9 ± 1.6 W·kg-1, 1457 ± 349 m, 7506 ± 1364 m, 107 ± 20 m·min-1 and 1169 ± 260 m respectively. Half-backs, midfielders and half-forwards outperformed full-backs (Effect Size [ES] = 1.03, 1.22 and 2.07 respectively), and full-forwards in Pmet (Effect Size [ES] = 1.70, 2.07 and 1.28 respectively), and HMLD (full-backs: ES = -1.23, -1.37 and -0.84 respectively, and full-forwards: ES = -1.77, -2.00 and -1.38 respectively). Half-backs (ES = -0.60), midfielders (ES = -0.81), and half-forwards (ES = -0.74) experienced a second-half temporal decrement in HMLD. The current investigation demonstrates that metabolic power may increase our understanding of the match-play demands placed on elite hurling players. Coaches may utilize these findings to construct training drills that replicate match-play demands

UNICELL ONTOGENY and PHYLOGENY: EXAMPLES FROM THE DIATOMS

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72275/1/j.1096-0031.1987.tb00511.x.pd

Cartel organization, price discrimination, and selection of transatlantic migrants:1899–1911

We study the effects of trans-Atlantic passenger shipping cartels on tourist/business and migrant traffic. Collusion had a smaller effect on first and second class service relative to third class service. Its effects were proportionately stronger eastbound, but less important in absolute numbers given smaller eastbound traffic. Collusion-driven consumer substitution across classes was small but non-negligible. Thus, collusion affected migrant traffic far more than tourist/business traffic. We also confirm that collusion led to higher fares across all cabin classes, especially for steerage. We construct and calibrate an analytical model and show that the pattern of observed prices and volumes are consistent with a profit-maximizing cartel, thus buttressing the hypothesis that the collusion effects were causal. Finally, we document that collusion led to positive selection of migrants, as measured by literacy rates and financial resources

Armadillo 1.1: An Original Workflow Platform for Designing and Conducting Phylogenetic Analysis and Simulations

In this paper we introduce Armadillo v1.1, a novel workflow platform dedicated to designing and conducting phylogenetic studies, including comprehensive simulations. A number of important phylogenetic and general bioinformatics tools have been included in the first software release. As Armadillo is an open-source project, it allows scientists to develop their own modules as well as to integrate existing computer applications. Using our workflow platform, different complex phylogenetic tasks can be modeled and presented in a single workflow without any prior knowledge of programming techniques. The first version of Armadillo was successfully used by professors of bioinformatics at Université du Quebec à Montreal during graduate computational biology courses taught in 2010–11. The program and its source code are freely available at: <http://www.bioinfo.uqam.ca/armadillo>

Analyses of 32 Loci Clarify Phylogenetic Relationships among Trypanosoma cruzi Lineages and Support a Single Hybridization prior to Human Contact

Trypanosoma cruzi is the protozoan parasite that causes Chagas disease, a major health problem in Latin America. The genetic diversity of this parasite has been traditionally divided in two major groups: T. cruzi I and II, which can be further divided in six major genetic subdivisions (subgroups TcI-TcVI). T. cruzi I and II seem to differ in important biological characteristics, and are thought to represent a natural division relevant for epidemiological studies and development of prophylaxis. Having a correct reconstruction of the evolutionary history of T. cruzi is essential for understanding the potential connection between the genetic and phenotypic variability of T. cruzi with the different manifestations of Chagas disease. Here we present results from a comprehensive phylogenetic analysis of T. cruzi using more than 26 Kb of aligned sequence data. We show strong evidence that T. cruzi II (TcII-VI) is not a natural evolutionary group but a paraphyletic lineage and that all major lineages of T. cruzi evolved recently (<3 million years ago [mya]). Furthermore, the sequence data is consistent with one major hybridization event having occurred in this species recently (< 1 mya) but well before T. cruzi entered in contact with humans in South America