Gregory Mark Erickson, PhD - US grants

In preliminary studies, we have developed a simple method for isolating a population highly purified undifferentiated ovarian interstitial cells which are free of granulosa cell contamination. Using this model, we have made the novel discovery that IGF-I can directly stimulate the undifferentiated cells to express their fully differentiated state in serum-free medium. These findings suggest the exciting hypothesis that a cAMP independent differentiation mechanism exists which may be mediated by a tyrosine kinase. In the proposed studies, we will use specific antisera and cDNA probes for key steroidogenic enzymes to probe the biochemical events that occur during differentiation stimulated by IGF-I in vitro. These events will be correlated with interstitial cell function at selected stages during folliculogenesis Experiments will be performed to test the hypothesis that IGF-I stimulates a tyrosine kinase which phosphorylates unique proteins that correlate with increased steroidogenic enzyme synthesis and message transcription. The mechanism of interaction between the IGF-I/tyrosine kinase pathway and the LH/cAMP pathway will also be examined. It will be determined if IGF-I action is totally independent of cAMP, or alternatively, if the IGF-I and LH pathways converge into a final common differentiation mechanism. Finally, the modulation of IGF-I action by estrogens, glucocorticoids prolactin, and epidermal growth factor will be examined. Thus, we will determine the role of IGF-I in regulating the differentiated state of the ovarian interstitial cells and examine how IGF-I fits into the current concept of multifactorial regulation of follicle development and atresia. We anticipate that by completing our research goals we will describe a new regulatory pathway for differentiation of ovarian interstitial cells which may be equally important to ovarian physiology as LH. These studies will provide new and important information regarding ovarian function which may open the door to novel therapies that exploit presently unknown regulatory mechanisms in the ovary.

In preliminary studies, we have developed a simple method for isolating a population highly purified undifferentiated ovarian interstitial cells which are free of granulosa cell contamination. Using this model, we have made the novel discovery that IGF-I can directly stimulate the undifferentiated cells to express their fully differentiated state in serum-free medium. These findings suggest the exciting hypothesis that a cAMP independent differentiation mechanism exists which may be mediated by a tyrosine kinase. In the proposed studies, we will use specific antisera and cDNA probes for key steroidogenic enzymes to probe the biochemical events that occur during differentiation stimulated by IGF-I in vitro. These events will be correlated with interstitial cell function at selected stages during folliculogenesis Experiments will be performed to test the hypothesis that IGF-I stimulates a tyrosine kinase which phosphorylates unique proteins that correlate with increased steroidogenic enzyme synthesis and message transcription. The mechanism of interaction between the IGF-I/tyrosine kinase pathway and the LH/cAMP pathway will also be examined. It will be determined if IGF-I action is totally independent of cAMP, or alternatively, if the IGF-I and LH pathways converge into a final common differentiation mechanism. Finally, the modulation of IGF-I action by estrogens, glucocorticoids prolactin, and epidermal growth factor will be examined. Thus, we will determine the role of IGF-I in regulating the differentiated state of the ovarian interstitial cells and examine how IGF-I fits into the current concept of multifactorial regulation of follicle development and atresia. We anticipate that by completing our research goals we will describe a new regulatory pathway for differentiation of ovarian interstitial cells which may be equally important to ovarian physiology as LH. These studies will provide new and important information regarding ovarian function which may open the door to novel therapies that exploit presently unknown regulatory mechanisms in the ovary.

Substantial evidence has been obtained which supports the concept that insulin-like growth factor I (IGF-I) is an autocrine/paracrine regulator of ovary function. Under physiological conditions, IGF-I is bound with high affinity to a family of binding proteins (the IGFBPs) which act to modulate, either amplify or attenuate, IGF-I action. Recently we have isolated, sequenced, and cloned the six rat IGFBPs (IGFBP -1,-2,-3,-4,-5,-6), and obtained preliminary evidence from Northern analysis that the messenger RNA transcripts for the IGFBPs are expressed in the rat ovary. To understand IGF-I function from a physiological perspective, we must understand the cellular localization and regulation of these six IGFBPs in ovary. This is the overall objective of this grant application. In the first aim, we will employ in situ hybridization to localize the cellular sites of the mRNAs for the six IGFBPs in rat ovary tissue throughout the estrous cycle. Interestingly, preliminary data suggest that each of the IGFBPs may be localized to a different population of endocrine cells. In the second specific aim, we will synthesize fragments of each of the IGFBPs and use them as antigens to elicit the production of antibodies. Then by immunocytochemistry we will characterize the cellular localization of the six IGFBPs in ovary tissue during the estrous cycle. In the last specific aim we will perform a series of classic endocrine ablation and replacement experiments to obtain basic information about the hormonal regulation of IGFBP production. Changes in the expression of the six IGFBPs will be monitored by in situ hybridization and immunocytochemistry. We expect that the results of these specific aims will provide primary answers to the "next step" questions in the field of IGFBPs in the ovary, and provide the rational for future studies of the regulation and function of the ovarian IGFBP system.

A central problem in mammalian reproductive biology is to understand the mechanisms by which a few follicles are selected to survive atresia to ovulate their eggs into the oviduct to be fertilized. It is clear that the concentration of FSH within the microenvironment has a critical role in regulating this process, eg. relatively high and low in levels of FSH in follicular fluid are associated with selection and atresia respectively. Despite intensive studies, the mechanism by which the concentration of follicular fluid FSH controls the developmental fate of a follicle remains largely unknown. During the course of this grant, we have made several novel discoveries that suggested that the level of FSH-induced granulosa cytodifferentiation is regulated, in part, by the production of two intrinsic proteins which might act in an autocrine/paracrine manner to inhibit folliculogenesis. These discoveries include: l) two novel genes, insulin-like growth factor binding protein -4 and -5 (IGFBP-4, -5) are induced in rat granulosa cells during atresia; 2) the levels of IGFBP-4 and -5 expression are regulated in a biphasic fashion by FSH e.g. low and high doses stimulate and inhibit IGFBP expression respectively; and 3) exogenous IGFBP-4 and -5 in vitro inhibit FSH-induced estradiol and progesterone production by granulosa cells. These results support the intriguing hypothesis that IGFBP-4 and -5 might serve as inducers of atresia in vivo. The challenge is to prove this hypothesis. At present, very little is known about how IGFBP-4 and -5 act and interact to regulate FSH-induced granulosa growth and cytodifferentiation in vitro, and nothing is known about their effects on folliculogenesis in vivo. The ultimate goal of this proposal is to fill this fundamental gap in our knowledge. Three specific aims are proposed. Specific Aim #1: to express recombinant rat (rr) IGFBP-4 and -5 in CHO cells and to generate polyclonal antibodies to the mature proteins. Specific Aim #2: to use the rrIGFBPs and their polyclonal antibodies to characterize the biological effects of these novel peptides on rat granulosa cells in vitro. In serum free cell culture, cells will be incubated alone and together with FSH, rrIGFBPs and/or their antibodies. After culture, the cells will be analyzed for differentiation markers, mitosis, and apoptosis. In parallel studies, the effects of these peptides on LH and prolactin induced responses will be examined. Specific Aim #3: to determine the effects of exogenously administered rrIGFBP-4 and -5 and their antibodies on granulosa proliferation, differentiation and apoptosis in vivo. Because IGFBP-4 and -5 are present in human follicles, an understanding of how these intrinsic proteins modulate, either amplify or attenuate, specific FSH-induced granulosa responses might provide new insight into ovulation disorders in women.

Recently, we discovered a protein which specifically inhibited the action of FSH in the granulosa cells (GCs). Upon characterization by molecular cloning, this protein was shown to be an insulin-like growth factor binding protein, 1GFBP-3. In the course of this study, we also isolated three novel IGFBPs and cloned their cDNAs in the rat and human, and named them IGFBP-4, -5 and -6. Our studies further yielded the findings that: (i) rat GCs of the follicles which progress to ovulation do not express any IGFBPs, whereas those which are destined to die by atresia selectively express IGFBP-4 and -5; (ii) exogenous administration of IGFBP-4 and -5 to the GC culture inhibit FSH-induced steroid synthesis; thus, these IGFBPs are potent FSH antagonist; (iii) FSH inhibits the expression of 1GFBP-4 and -5 in the cultured GCs, and degrades these IGFBPs by FSH-induced protease(s); (iv) GnRH-agonist dose-dependently stimulates the expression of IGFBP-4 and -5 in the cultured GCs, and abolishes the ability of FSH to inhibit IGFBP-4 and -5 expression and to induce their protease activity. These findings led us to propose the intriguing and exciting hypothesis that the expression of these IGFBPs may lead to atresia by virtue of their ability to antagonize FSH action. The challenge is to prove this hypothesis. The ultimate goal of this proposal is to explore what controls the timing and level of IGFBP-4 and -5 expression during folliculogenesis and how they regulate the expression of these IGFBPs at the transcriptional and post-transcriptional levels in the rat GCs. Three specific aims are proposed. SPECIFIC AIM #1: To characterize the temporal pattern of expression of IGFBP-4 and -5 mRNAs and proteins in non-dominant cohort follicles during the process of atresia as it occurs physiologically over the estrous cycle, and to investigate how selectogenic and atretogenic ligands modulate IGFBP-4 and -5 mRNA and protein expression in vivo. SPECIFIC #2: To explore the control of the IGFBP-4 and -5 gene expression in the GCs at transcriptional and post-transcriptional levels in vitro. SPECIFIC AIM #3: To characterize the gene promoters responsible for controlling basal and regulated levels of IGFBP-4 and -5 transcription. The findings from the proposed studies may shed new light in understanding the mechanisms by which follicle selection and atresia are regulated; and thus, they could have new and important implications for fertility and infertility in women.

Abstract DBI 9750190 Gregory M. Erickson This action funds an NSF Postdoctoral Research Fellowship in Biosciences Related to the Environment for 1997. This fellowship provides an opportunity for the Fellow to gain additional scientific training beyond the doctoral degree and to pursue innovative and imaginative into the fundamental mechanisms underlying the interactions between organisms and their environment at the molecular, cellular, organismal, population, community and/or ecosystem level in any area of biology supported by the Directorate for Biological Sciences of the National Science Foundation. Each fellowship supports a research and training plan to be carried out in a sponsoring laboratory. The research and training plan for this fellowship is entitled "How bones of amphibious fish are modified for terrestrial locomotion during evolutionary water-to-land transitions." The emergence of vertebrates onto land was made possible by biomechanical modification of the appendicular skeleton. The nature of such changes is being determined by testing the biomechanical properties of bones from amphibious fish and their aquatic sister taxa. The results are important for understanding how bone form and function are regulated by mechanical demand during evolution.

Questions concerning the regulation of folliculogenesis are clinically important because alterations in the process can lead to pathophysiology and infertility. Recently, a novel TGF-Beta family member, GDF-9 is ovary specific, being localized exclusively to oocytes. The importance of GDF-9 deficient mice is arrested and the females are infertile. Accordingly, GDF-9 secreted by the egg is obligatory for folliculogenesis and fertility. The clinical relevance of this new concept is demonstrated by the presence of GDF- 9 mRNA in the human oocyte. At present, virtually nothing is known about the mechanisms controlling GDF-9 expression, and nothing is known about the target cells for GDF-9 and the biological process that GDF-9 regulates. The purpose of this grant is to fill these fundamental gaps in our knowledge of GDF-9 in rat and human ovaries. Three specific aims are proposed: AIM1. Determine the cellular localization and changing pattern of expression of GDF-9 mRNA and protein by in situ hybridization and immunocytochemiestry, respectively, in human (normal and abnormal) and rat ovaries at various reproductive states and during aging. The latter could have implications for aged-related infertility. Novel preliminary data show a dramatic decrease in GDF-9 mRNA during atresia. AIM 2. Test the hypothesis that atretogenic endocrine and autocrine/paracrine ligands negatively regulate GDF-9 expression and promote atresia. Using the immature rat, we will investigate the effects of known atretogenic hormones (testosterone, GnRH, low dose hCG, estrogen withdrawal, prolactin, growth hormone) on oocyte GDF-9 levels, and correlate the effects with changes in granulosa cell mitosis and apoptosis. Novel preliminary data indicate that prolactin and growth hormone cause dramatic decreases in GDF-9 mRNA which are accompanied by the cessation of granulosa mitosis. Aim 3 Using recombinant human GDF-9, we will 1) determine the target cells for GDF-9 in rat and human ovaries by in situ autoradiography; 2) characterize the binding constants of the GDF-9 receptor by Scatchard analysis; and 3) elucidate the biological consequences of GDF-9 action in granulosa cells cultured in serum free medium. Novel preliminary data indicate theat rhGDF-9 acts on granulosa cells to stimulate mitosis. We anticipate that the results from our experiments will also suggest new targets and avenues for managing fertility and infertility.

The evolution of many species was facilitated by changes in feeding capacity. Extensive testing has shown modifications in tooth size, shape, and biting forces are critical determinants of feeding capacity. However, changes in the mechanical performance of dental tissues, which may also play an integral role in this process, are little understood. Data regarding material level mechanical capacity is lacking since dental tissues are minute and preclude most testing protocols. In the present research this problem will be overcome using a new engineering technique called nano-indentation (miniaturized mechanical testing) whereby the measurement of strength, hardness, and scratch-resistance of small materials is feasible. The method will be applied to enamel (the primary contact tissue between food items and the dentition) from a diversity of species with a broad range of feeding abilities.
The data generated from this study will serve to tie together the current data on dental morphology and biomechanics. Furthermore it will move the field considerably closer to a comprehensive understanding of the form, function, and ecology of animal feeding--past and present--including how and why our own dentitions function as they do.

ABSTRACT: COLLABORATIVE RESEARCH--
LIFE HISTORY STRATEGIES, GROWTH RATES AND
MICROSTRUCTURAL CHARACTEREVOLUTION ACROSS THE
COELUROSAURIAN/AVIALAN TRANSITION

Gregory M. Erickson. Kristina Curry-Rogers, Mark Norell

Birds (avialan dinosaurs) are unique among living animals in showing extremely rapid growth rates. How they attained this capacity is unknown. In our research we will reconstruct the growth of the earliest birds and their closest ancestors, the coelurosaurian dinosaurs. We will do this by coupling age estimates (garnered through growth line counts) with size estimates for a diversity of fossil species. From the results we will be able to quantitatively assess when and how avian growth rates were generated and determine whether the first birds were simply feathered dinosaurs or physiological equivalents to living species. Aside from helping us to understand how the most speciose group of animals living in our world came to came to be, broader impacts of this research include: 1) establishing a World Wide Web site from which the lay pubic and professions can learn about scientific research, 2) providing advanced scientific training to undergraduate and graduate students including those from underrepresented groups, and 3) providing material for our public and non-major collegiate lectures in paleontology.

Ceratopsians are among the best known of dinosaur clades due to their
relative abundance, and the remarkable diversity of cranial synapomorphies such as horns
and frills that diagnose more derived members of the clade. Gigantism is a trend in
ceratopsian evolution that is accompanied by the evolution of progressively more
complex feeding mechanisms and cranial display diversity. Heterochrony, and in
particular peramorphosis have been proposed as major influences in ceratopsian
evolution to explain the evolution towards large size and late ontogenetic genesis of the
display in advanced forms. Likewise, the apparent hierarchical complexity of the feeding
apparatus suggests an evolution of character integration through both ontogeny and
phylogeny. All of these evolutionary hypotheses require detailed knowledge of both the
development and phylogeny of ceratopsian dinosaurs, but so far age estimates have been
poorly constrained and non-quantified and rigorous reliance on detailed phylogenies
limited.
In this study, an innovative approach to developmentally staging fossils based on
histological sectioning and Developmental Mass extrapolation is combined with novel
tree-based methods toward studying heterochrony and integration using a well-
established phylogeny of Ceratopsia. Based on well-sampled growth series of seven
backbone taxa representing the diversity of the clade, and a detailed phylogeny of
ceratopsians, we will examine whether there are correlated shifts in developmental timing
of synapomorphies (heterochrony) relative to growth strategies, and also if blocks of
characters represent integrated modules that fulfill criteria for being phylogenetically and
ontogenetically constrained. These quantitative studies will allow us to evaluate previous
hypotheses on the role heterochrony and integration have played in ceratopsian evolution.
By providing a quantified understanding of when in ontogeny synapomorpies are
expressed this research will help to resolve several taxonomic quandaries related to the
validity of species based on juvenile holotypes and provide a more accurate
understanding of ceratopsian diversity.
Broader Impact: This research represents a new integrative exploration of evolutionary
processes in a well-known group of dinosaurs. The novel methods and the results of this
research promise to be widely applicable to fields as diverse as population biology,
developmental biology, macroevolution and evo-devo, and will be disseminated through
peer -reviewed journals, presentations at professional meetings and professional web-
sites. Two graduate and two undergraduate students will be trained through this project,
and aspects of the research will be incorporated into university courses taught by both
PIs. Both PIs are involved with developing exhibits for natural history museum, and
parts of this research will be incorporated into two ongoing exhibit projects, and
associated educational web-sites and programming. Given the media interest in dinosaur
research, many opportunities to disseminate results of this work to the public will no
doubt arise.

A grant has been awarded to the Florida State University under the direction of Dr. Fredrik Ronquist for partial support of the acquisition of a scanning electron microscope with a field emission gun, a variable-pressure specimen chamber, a cryotransfer unit, and an elemental microanalysis unit. The equipment will offer a number of microscopic examination techniques that are not available today in the north Florida region and will be used by biologists, chemists, engineers, and geologists at the Florida State University and the Florida Agircultural and Mechanical University and by colleagues at other universities and colleges in the region.

The field emission gun allows imaging with extraordinary contrast and large depth of focus at both low and high magnifications. It also gives greatly improved performance at low acceleration voltages, which allows high-magnification examination of uncoated samples or samples that have a tendency to charge and alter in the electron beam. The possibility of raising the pressure in the examination chamber by introducing a gas can also help in the examination of sensitive samples. The cryotransfer equipment is used for rapid freezing of a specimen for subsequent transfer in the frozen state into the microscope chamber. With this equipment it is possible to observe unfixed frozen material in its natural state. Finally, the X-ray microanalysis equipment allows analysis of the composition of the sample surface.

The new instrument will be used for a wide range of applications including studies of polymers; cellular and tissue details important in medical engineering; /Drosophila/ mutants; teeth and other skeletal structures in dinosaurs, birds and mammals; skeletal morphology of hymenopterans (ants, wasps and bees); flower morphology; and structure of clays and fossil diatom assemblages in deep sea sediments. Five research groups in Chemistry are studying different types of novel materials based on nano-scale manipulation. The new microscope equipment will support the research of many faculty members but will also be used in education and research training of underrepresented groups. Other examples of activities with broad impact that will benefit from the new equipment include Sir Harold Kroto's efforts to popularize science through the Vega Science Trust, the first free Internet broadcaster of science programs, and the MorphBank project, aimed at providing a web platform for international collaboration in image-based biological disciplines such as comparative morphology and biodiversity research.

Florida State University is granted an award to enhance the MorphBank Image database. Many biological disciplines rely for their data primarily on observations of appropriately prepared specimens. A few examples include comparative anatomy, histology, morphological phylogenetics, and taxonomic research. The need for access to suitable specimens constitutes a significant hurdle to rapid progress in these disciplines. However, in many cases data of comparable quality can be generated from photographs of the specimens instead of from the specimens themselves. The development of fast Internet connections and the availability of low-cost high-quality digital imaging techniques is currently revolutionizing research and teaching in these disciplines, and recent years have seen a rapid proliferation of 2D- and 3D-image databases of biological specimens on the web. MorphBank (www.morphbank.net), not to be confused with MorphoBank, is a searchable web repository of images for comparative morphology and biodiversity research, originally conceived by a consortium of Swedish, Spanish and American systematic entomologists. It currently contains about 6,000 images documenting morphological phylogenetics analyses, newly described taxa, and voucher specimens tied to GenBank sequences. MorphBank has been open to the user community for uploading of images since early 2003 and works well as a searchable image archive. The next steps in the development of specimen image databases focus on three projects, each exemplifying one important use case for such databases: (1) large phylogenetics projects; (2) remote annotation of natural history collections; and (3) comparative histology projects. The interdisciplinary research team, which includes biologists, computer scientists, a mathematician, and information retrieval specialists, will develop general technology that can easily be adapted to address the specific needs of each of these use cases, facilitating the incorporation of additional use cases in the future. In particular, the team will develop community annotation technology, making it possible for researchers to link their observations to specific images, without compromising the original image, and enabling their colleagues to search, process and comment on these annotations. The team will also develop the MorphBank user interface including a new image-handling client, develop networking technology to support database functionality, substantially revise and refine the table structure, and implement more sophisticated data filtering and backup technologies. Finally, the team aims to build an international network of institutions supporting MorphBank or MorphBank-compatible image databases and to spur the development of international standards for biological image databases. The MorphBank project provides ample opportunities for supporting educational and outreach activities through its open access to biological images and associated information.

Abstract
COLLABORATIVE RESEARCH: EVOLUTION OF THE HADROSAURID DENTITION--HISTOLOGICAL AND BIOMECHANICAL INSIGHTS INTO ADVANCED REPTILIAN HERBIVORY
Gregory M. Erickson and Mark A. Norell
Throughout their 300+ million year history, herbivorous reptiles rarely acquired teeth that allowed for chewing in the manner of ungulate mammals (e.g. horses and cows). The lone exception was the duck-billed dinosaurs (aka hadrosaurids), the dominant herbivores of the Late Cretaceous. In our research we are studying: 1) the steps by which hadrosaur teeth became more complex, 2) how the mechanics of their dentition changed with each step, 3) how such changes allowed for the processing of different food types, and finally 4) how their extensive worldwide radiations were made possible by dental changes. We are specifically documenting the shape and microstructure of the teeth throughout the group, including some of the earliest and latest representatives. From growth lines found in the samples we are determining how long each dinosaur?s teeth took to form, wear down, and be replaced. We are then using these data to create computerized engineering models of the dentitions and using them to explain how the chewing surfaces of each species were created. Ultimately we will correlate these data with dietary information and geographic radiations to gain a comprehensive understanding of how hadrosaurids came to dominant herbivorous roles during the age of dinosaurs. The results will serve as a model for understanding the genesis of complex dental structures and will be of interest to investigators in myriad scientific disciplines (e.g. vertebrate paleontology, paleobiology, evolutionary biology, anthropology, integrative biology, comparative physiology, ecology, herpetology, and mammalogy). Additional benefits of this study include educational opportunities for students and teachers. Justifications and descriptions of the research and findings will be posted on the internet for public access along with an archive of research images. Through the American Museum of Natural History (AMNH) Education Department?s summer intern program, high school students have the opportunity for hands-on participation in the project. Teacher training (for high school and middle school teachers) will also be conducted as a result of this grant. Teacher Professional Development Workshops, focusing on dinosaur evolutionary feeding ecology, will be held at the Gottesman Center at the AMNH. In addition this research will be shared with teachers who participate in hands-on histology activities during a special continuing education program at Florida State University.

COLLABORATIVE RESEARCH: ARCTIC DINOSAUR PALEOBIOLOGY: HYPOTHESIS TESTING THROUGH CROSS-LATITUDINAL COMPARISON

Principle Investigator: Patrick Druckenmiller, University of Alaska Fairbanks
Co-Principle Investigator: Gregory M. Erickson, Florida State University, Tallahassee

Polar dinosaurs endured intense seasonal conditions making them well suited to test major questions in dinosaur paleobiology pertaining to physiology, migration and distribution. This project will examine the most prolific, yet vastly understudied polar dinosaur fauna known, the Prince Creek Formation of northern Alaska. The research will entail collection, description, and assessment of species composition. These data will be compared to those of lower latitude formations affording the first comparison between a polar dinosaur fauna and typical lower latitude dinosaurian assemblages. The study will also document the influence of the Alaskan Arctic environment on dinosaur biology through analyses of bone and tooth growth rings. Learning how dinosaurs occupied the Arctic will provide new insights into high latitudinal occupation by animals as a whole. This project will bring together a diverse team of scientists who will share new ideas and methodologies and contribute to the education and training of graduate and undergraduate students. Results will be submitted to scientific journals and presented publicly on the Internet. Visits will be made to rural, northern Alaskan K-12 schools to provide underserved Alaska Native students and teachers with an opportunity to learn about the fossils in their area and interact with NSF-sponsored researchers.

The 70-million year old Prince Creek Formation of Arctic Alaska provides fossil evidence that a surprisingly diverse array of dinosaurs, birds, flying reptiles and small mammals lived in polar forests characterized by warm summers and five- to six-months of darkness and snowfall during the polar winter. Enduring these seasonally intense and variable conditions makes these animals uniquely suited to test major paleobiological questions pertaining to physiology, migration, body size changes, ecology and distribution. This project will examine these questions through new Arctic specimen collections and identifications, temperature determinations and growth studies, and comparison to findings with animals living at warmer lower latitudes. This project will bring together a diverse team of scientists who will share new ideas and methodologies and contribute to the education and training of graduate and undergraduate students. Results will be disseminated in scientific venues and presented publicly through museum exhibitions and K-12 presentations. The latter will include visits to rural, northern Alaskan schools to provide underserved Alaska Native students and teachers with an opportunity to learn about the fossils in their area and interact with NSF-sponsored researchers.

Using macro- and microfossil remains, this study will establish a comprehensive dataset on the faunal composition of a Mesozoic polar assemblage, including descriptions of probable new species unique to the Arctic. Statistical techniques will be used to compare the faunal compositions between mid- and high latitudes to understand North American distribution patterns. Histological analyses of bones and teeth will provide the first rigorous testing of the affects of polar environments on the growth and physiology of dinosaurs and mammals. Lastly, a novel technique using biomarkers will be used to provide more precise paleotemperature estimates to understand the temperature regime experienced by the polar fauna.