Faculty Research Area: Neurobiology & Behavior
Macrophages are highly dynamic and widespread blood cells that play many important functions in vertebrates. They are the main phagocytes throughout the body, responsible for clearing away dying cells, damaged tissue, and pathogens, to maintain tissue integrity. Macrophages circulate in the bloodstream as monocytes or are stationed in strategic locations of the body as tissue macrophages where their phagocytic roles are critical, such as microglia in the brain, Kupffer cells in the liver, Langerhans cells in the skin, and osteoclasts in the bone.
Of particular interest are the normal roles and mechanisms of macrophages and microglia in the development and maintenance of the nervous system that remain far less understood than their functions in disease and injury. In the healthy brain, microglia have been implicated in shaping brain circuitry and neuronal development as well as in possibly affecting behavioral outcomes. They have unique embryonic origins from primitive macrophages that migrate into the brain and remain thereafter through life. These versatile glial cells provide the first line of defense and respond to a wide variety of environmental factors, such as protein aggregates, apoptotic cells, injured tissue, and pathogens, as well as to intracellular dysfunctions. Overall, the developmental process by which macrophages take residence and differentiate into tissue macrophages, and the contribution of macrophages to normal animal development remain not well understood. We are addressing these two fundamental areas of macrophage biology in the context of how macrophages participate in the nervous system.
My research has focused on field studies of complex social behavior by birds and other animals. Topics have included long-range vocal communication by temperate and tropical birds, vocal communication in noisy conditions (colonies, choruses, rainforests), sexual conflict and monogamy in territorial birds, sexual selection in polygynous mating systems and leks, site-specific dominance in wintering birds, and cooperative breeding in tropical wrens.
Continuing themes in all of these studies are age-dependent behavior, recognition of individuals, and impacts of noise on communication. My goal is to understand the complexity of animal social behavior … especially communication.
Facilities for this research include up-to-date equipment for recording, display, and synthesis of acoustic signals. My students, postdoctoral associates, and I have conducted field research both locally and far afield, including throughout the American tropics.
For more information, including publications, see http://rhwiley.bio.unc.edu.
Our lab group is interested in the behavior, sensory biology, neuroethology, and conservation of marine animals. Topics of particular interest include: (1) the navigation of long-distance ocean migrants such as sea turtles, salmon, spiny lobsters, and elephant seals; (2) magnetic field perception, magnetic maps, and use of the Earth’s magnetic field in animal navigation; (3) natal homing and the geomagnetic imprinting hypothesis in sea turtles and salmon; (4) applications of sensory ecology and movement ecology to conservation biology; (5) neurobiology, behavior, and physiology of marine invertebrates; (6) marine ecosystems and animal health in the Galapagos Islands. Techniques used range from electron microscopy, immunohistochemistry, and electrophysiology to behavioral studies, oceanographic modeling, and field studies in the ocean. Whenever possible, we favor innovative approaches that cut across traditional academic boundaries and combine elements from disparate fields.
Our lab group is interested in the sensory biology, behavior, neuroethology, and evolution of marine animals. Topics of particular interest include: (1) the navigation of long-distance ocean migrants such as sea turtles, salmon, and spiny lobsters; (2) magnetic field perception, magnetic maps, and use of the Earth’s magnetic field in animal navigation; (3) natal homing and the geomagnetic imprinting hypothesis in sea turtles and salmon; (4) applications of sensory ecology and movement ecology to conservation biology; (5) neurobiology, behavior, and physiology of marine invertebrates; (6) technoethology (the use of novel computer and electronic technology to study behavior). Techniques used range from electron microscopy, immunohistochemistry, and electrophysiology to behavioral studies, oceanographic modeling, and field studies in the ocean. Whenever possible, we favor innovative approaches that cut across traditional academic boundaries and combine elements from disparate fields.
Reproductive decisions are basic to all organisms. For species with multiple offspring and parental care, the decisions can be complex, but they still revolve around the same fundamental questions: when, where, and with whom to reproduce and how to invest in offspring. These decisions invariably have important life-history implications on future reproduction, on the offspring themselves, and on fitness.
Using birds, the Sockman lab studies the causes and consequences of reproductive decisions. Birds are an excellent system for this topic, because their decisions are often easy to observe and apply across a broad range of taxa and habitats. Follow the links above to learn more about our program or, if you are a prospective student, to learn about joining the lab.
If you want to list me as a reference or need a letter of recommendation, please use this guide from the UNC Biology Department website and include in your e-mail to me a PDF file of this document filled out and signed by you. Please see my laboratory website for other information.
At a Glance
Environment-dependent behavior, hybridization, mating behavior evolution, sexual selection, speciation and species distributions.
The overarching goal of my research is to understand how behavior drives the origins and distribution of biodiversity. Because mate choice is a potent selective force that can be critical in the formation of novel phenotypes and new species, I focus on the evolution of mating behavior and its role in ecological and evolutionary processes. I work with natural populations and use a variety of approaches ranging from behavioral experiments to genetic analyses. For more details, including references, please go to my lab website.
I’m broadly interested in the interplay among evolution, ecology, and development. My current research focuses on three main topics.
First, I study the causes and consequences of a common feature of development: its tendency to be responsive to changes in the environment. Although biologists have long known that an individual organism’s appearance, behavior, and physiology can be modified by its environmental conditions, the implications of such developmental (or phenotypic) plasticity for ecology and evolution remain poorly understood. Moreover, the underlying genetic and developmental mechanisms that foster plasticity’s evolution are unclear. I seek to understand the impacts of plasticity on diversification and evolutionary innovation, as well as how and why plasticity arises in the first place.
Second, I study the role of competition in generating and maintaining biodiversity. I’m particularly interested in unravelling whether and how competition promotes trait evolution and the impacts of any such evolution on the formation of new traits and new species.
Finally, I study a striking form of convergent evolution known as Batesian mimicry, which evolves when a palatable species co-opts a warning signal from a dangerous species and thereby deceives its potential predators. Such instances of “life imitating life” provide an ideal opportunity to assess natural selection’s efficacy in promoting adaptation.
For more details on my lab and research, please visit my lab page by clicking on the link above.
At a Glance
- Speciation and the evolution of premating isolation
- Sexual selection and the evolution of mate choice
- Learning and cultural evolution
- Evolution of behavior
I am interested in a broad range of topics from evolutionary genetics to behavioral ecology. I explore these topics through the techniques of theoretical biology. My main goal is to use mathematical models to integrate rigorous evolutionary theory with hypotheses explaining behavioral and ecological patterns and phenomena. I am excited to provide integrated approaches to these questions by combining mathematical with experimental, genetic, and comparative techniques through collaborations with students and colleagues.
A large portion of my current work explores mechanisms that drive speciation through the evolution of premating isolation. One of the primary adaptive hypotheses for this evolution is that it occurs through the process of reinforcement, where it is driven by selection against the production of unfit hybrids. I have been exploring reinforcement by trying to pinpoint the forces of selection and genetic associations that cause evolution of alleles for female preferences for conspecific males. A current focus in this area is how speciation processes are affected when mating preferences and/or mating cues are influenced by learning.
An additional area of interest is mate choice, with a particular focus on male mate choice. I have used several different approaches to explore the question of whether male mate choice would be expected to evolve during polygyny. Other projects on mate choice include the effects and evolution of learning on sexual selection.
For more information, please see my lab web page.
Adaptations are central to the study of evolution. Thus it is surprising that we know so little about the molecular basis of adaptive evolution. The goal of my research is to identify, clone, and characterize the evolution of genes underlying natural adaptations in order to determine the types of genes involved, how many and what types of genetic changes occurred, and the evolutionary history of these changes. These data will address key questions. For example, do adaptations involve many genetic changes or only a few? How important are regulatory versu! s amino acid changes in adaptation? How often are “new” gene s involved in adaptations? Are most adaptive alleles new mutations or pre-existing alleles segregating at low to moderate frequency within a species? Clearly, a deeper understanding of how genes change during adaptation will give insight into the potential and limits of adaptive evolution.
Spatial patterns of genomic features
I am also using genomic data to address important evolutionary questions. Recently, I used D. melanogaster genome sequence data to estimate genome-wide levels of gene clustering and to contrast the amount of clustering among genes with similar motifs to the levels of clustering in general. All chromosomes, except the fourth, showed substantial levels of gene clusteri! ng. Although not more clustered than the average pair of adjacent genes, genes with the same primary motif occur adjacent to one another more often than expected by chance. These results may mean that these small local groups of genes share regulatory elements and evolutionary histories.
Detecting natural selection in DNA sequence data
Molecular evolutionists have long sought to determine which changes within the protein coding and regulatory regions of a gene were shap! ed by natural selection. If an adaptive substitution has occurred in the recent past, there should be a paucity of DNA polymorphism surrounding the site under selection. Taking advantage of this fact, Andrew Kern and I have developed a permutation approach for detecting selected sites using polarized DNA polymorphism and divergence data. This method is especially useful for detecting the effects of weak selected forces across several loci. We used this approach to analyze a large DNA polymorphism and divergence data set of D. simulans genes. Surprisingly, although replacement fixations do not on average appear to be driven by selection, preferred codons – those codons that use the most abundant tRNA – have on average been fixed by selection. We plan to apply this method to additional data sets and to look at spatial patterns of nucleotide fixation within and around genes. For instance, one could see if there is a bias in the types of polymorphism (sy! nonymous vs. non-synonymous) nearest to a type of fixation. This would give insight into the dynamics of the fixation process and its impacts on adjoining variation.