Dispersal analysis of three species based on landscape genetics data.

Lichens can either disperse sexually through fungal spores or asexually through vegetative propagules and fragmentation. Understanding how genetic variation in lichens is distributed across a landscape can be useful to infer dispersal and establishment events in space and time as well as the conditions needed for this establishment. Most studies have sampled lichens across large spatial distances on the order of hundreds of kilometers, while here we sequence the internal transcribed spacer (ITS) for 113 samples of three species sampling at a variety of small spatial scales.

Developmental constraints and convergent evolution in Drosophila sex comb formation.

The most complex and diverse secondary sexual character in Drosophila is the sex comb (SC), an arrangement of modified bristles on the forelegs of a subclade of male fruit flies. We examined SC formation in six representative nonmodel fruit fly species, in an effort to understand how the variation in comb patterning arises. We first compared SC development in two species with relatively small combs, Drosophila takahashii, where the SCs remain approximately transverse, and Drosophila biarmipes, where two rows of SC teeth rotate and move in an anterior direction relative to other bristle landmarks.

Cell dynamics and developmental bias in the ontogeny of a complex sexually dimorphic trait in Drosophila melanogaster.

The Drosophila sex comb (SC) has been hailed as a powerful tool for integrative studies in development, evolution, and behavior, but its ontogeny is poorly understood, even in the model organism Drosophila melanogaster. Using 4D live imaging and other techniques, we carried out a detailed analysis of the cellular events that take place during the development of the SC. We showed that the comb and other contiguous bristle formations assemble from noncontiguous precursor cells, which join together through intercalation.