Research Interests My interests lie at the point of intersection of multiple fields: where phylogenetics and population genetics approaches can inform questions of recent speciation, where coalescent approaches can help to discriminate among biogeographic hypotheses, and where molecular ecology and simulation-based analyses can discriminate among demographic scenarios. And knitting.
			Emballonura skins at the Field Museum, Chicago, IL

Current Research

• Using multilocus analyses of fecal samples from wild populations of chimpanzees and bonobos, we are (1) addressing standing taxonomic questions within P. troglodytes, (2) reconstructing the historical demography of Pan under the isolation-with-migration model, and (3) inferring patterns of population structure and growth within and between chimpanzee subspecies (Russell et al., in prep.).

• We have observed patterns supporting a complex demographic history for Pan. To further explore these data, we are using population and spatially explicit coalescent simulations to determine whether the observed data can be explained by a null model of simple splitting in a panmictic population or whether a more complex demographic model involving ancestral population structure or admixture is required.

• Comparisons of diversity at sex-limited loci in great ape species are revealing different demographies in different taxa, including evidence of significant reproductive skew and/or sex-biased dispersal in several species (Russell et al., in prep).

• An investigation of the molecular evolution of Alu retroelements in great apes is revealing evidence of (1) lineage-specific differences in rates of evolution at Y-linked Alu elements and (2) an increased rate of evolution in regions flanking the elements (Russell and Hammer in prep). We are using a comparative genomic approach to determine whether this pattern is upheld across the genome and an intensive population-level re-sequencing study to determine the point in time at which this change in evolutionary rate was effected.

Irons in the fire

1. A synthetic approach to studies of biogeography, in which coalescent and population genetic analyses are combined with more traditional phylogenetic analyses to construct a framework for testing logical series of hypotheses (Yoder et al. 2005). We have tested the utility of this new approach with a dataset from a genus of Old World leaf-nosed bats, Triaenops (Russell et al. 2007). More recently, we have applied Jody Hey's isolation-with-migration model to determine the directionality and timing of dispersal events between Madagascar and mainland Africa that resulted in major speciation events in this clade (Russell et al., in press).

2. A test of the peripatric model of speciation in a pair of closely-related mouse lemur species (Lemuridae: Microcebus). Despite significant levels of shared ancestral polymorphisms between the focal species, we are able to use a combination of coalescent and population genetic analyses to discriminate between alternative speciation hypotheses (Heckman et al., in prep.).

3. An exploration of the population genetics of the Brazilian free-tailed bat, Tadarida brasiliensis (Chiroptera: Molossidae) (Russell and McCracken, 2006). In one part of this project, my collaborators and I tested whether differences in migratory behavior have resulted in the genetic differentiation of regional populations, incorporating coalescent simulations to determine the relative influence of incomplete lineage sorting vs. ongoing gene flow on the data (Russell et al. 2005).

   In a second phase of this project, my collaborators and I are examining the role of behavior and continental-scale distances on genetic structure in this highly mobile species (Russell et al., in prep).

   A third offshoot of this project involves using coalescent simulations to analyze the contribution of human agriculture to patterns of demographic growth in Mexican free-tailed bat populations. Enormous populations of these bats are observed today and have been documented from the recent past; ecological research from Gary McCracken's lab has shown that these populations are largely dependent on agricultural pest insects such as corn earworms and cotton bollworms. These patterns suggest that bat populations have undergone population growth associated with the large-scale growth of human agriculture and the concommitant growth of associated pest insects. We are using coalescent simulations to (1) determine the statistical power available to detect growth in populations of this magnitude and over such recent timescales, and (2) to estimate population parameters (ancestral N_e, current N_e, time of onset of growth, and growth rate) consistent with the observed data (Russell et al., in prep).

4. A comparative phylogeographic study of Pteropus fruit bats in Samoa and Tonga. This study is revealing novel ways in which alternative behavioral adaptations for surviving periodic Pacific cyclones can result in dramatically different patterns of population genetic structuring among islands (Russell et al., in prep.)

5. The description of new species of bats in Madagascar and reconstruction of the demographic histories of these new taxa. Collaborative efforts have resulted in the description of two new species in the genera Myzopoda (Russell et al. in press) and Emballonura (Goodman et al. 2006).

6. Applications of phylogenetics to conservation biology. I have analyzed DNA from road-killed, morphologically unidentifiable bats within a phylogenetic framework to positively identify them as Myotis sodalis, the federally-protected Indiana bat. This study helped to protect a bat colony in Canoe Creek State Park, Pennsylvania, from a proposed highway widening project (Russell et al., in prep.).

	Future Projects: I'm interested in combining approaches from the fields of phylogenetics and population genetics, along with recent developments in coalescent theory, and applying them to questions of speciation and biogeography. And I'd like to see Scotland..
	A mitochondrial signpost.