General Interests: “We Study Weird”
Work in the Diaz Lab is truly integrative, collaborative and framed around the evolution, diversification and development of reptiles. From molecular biology to field work, we also have an active breeding group of reptiles in house that provide us embryos for various EvoDevo projects (>10 species across various families). We find that working with non-typical ‘model’ organisms provide both a challenge to study and also significant scientific return by simply teaching us how cool body plans form and have evolved relative to outgroup morphologies. We also frame our studies of reptiles within the context of how some features may appear as pathological morphologies in humans yet adaptive in nature, such as the cleft in the hands/feet of chameleons. Below are areas of current investigation:
General Comparative Embryonic Development Across Reptiles
To understand how body plans diversify across reptiles, we must first document morphogenesis of embryos for various groups. Currently we are putting together a collaborative book on Reptile embryonic development spanning all major reptile groups. From this data we can then examine at which point during development species either share the most similarities or present major lineage specific changes. Thus, giving us time points during development at which we can examine the genetic and cellular basis of morphological divergence.
Skull Development and Evolution
We take a broad approach at examinging the development of the vertebrate skull. In fact, the lab has projects utilizing the “classic” alizarin/alcian staining method to look at the formation of the cranioskeleton in amphibians and amniotes. Our focus the last several years has been to better understand the formation of individual elements in the squamate skull and use this speciose clade as a model for how the craniofacial complex evolves in both shape and number of cranial bones. Additionally, we hope to begin examining cranial neural crest cells across squamates with an examination of skull suture biology at various scales.
Limb Development and Interdigital webbing
Limbs are crucial for locomotion (along with axial anatomy). We have studied chameleon limb morphogenesis with respect to general growth and differentiation of the skeleton, with particular interest in the number of carpal and tarsal elements through ontogeny. Additionally, we plan to further examine the maintenance and loss of interdigital tissue in limbed reptiles at cellular and genomic levels while also examining what affects the number of skeletal elements in the autopodium.
Musculoskeletal and soft tissue development in the reptilian limbs
Muscular anatomy is a classic field in comparative morphology. In the lab we are using antibody staining to examine the formation and differentiation of limb musculature across ontogeny while also using in situ hybridization to study the formation and differentiation of tendons and ligaments. Reptiles have received little attention in this field. We have examined muscular architecture in a select group of chameleons and outgroup lizards and will be examining a finer scale series of questions ranging from muscle cell differentiation to myoblast fusion to what determines the patterning of muscles in lizards and snakes.
Neural Crest Cell Biology: From the Face to the Skin
Neural Crest Cells are a specialized pluripotent and transient cell types originating during neurulation from the dorsal or lateral aspect of the neural tube. NCCs have been considered to be crucial to the origin of craniates/vertebrates (build the face and contribute to a vast array of organs and tissues across the body). We are taking strides at examining their biology in reptiles. We recently described the origin, migration and differentiation of neural crest cells in the veiled chameleon and will be examining their role in craniofacial morphogenesis as well as their differentiation into skin pigments along with the patterning of such pigment cells to form the elegant and attractive patterns of colors we see in reptile skin. Additionally, we are interested in combining ‘omics data, cell biological data, wholemount immunohistochemistry and brightfield images of pattern formation during embryogenesis to develop biomathematical models for the formation and evolution of colors and patterns in squamate skin.
We believe that research questions should be approached through various approaches and techniques. We use histology (paraffin, frozen), electron microscopy (SEM, TEM), MicroCT (with and without contrast enhancing with Phosphotungstic Acid and Iodine; Amira Software for visualization), Immunohistochemistry (on sections and wholemount with fluorescence or HRP), PCR and cloning with/without reference genome for in situ hybridization to identify gene expression patterns (recently collaborated on assembling a veiled chameleon embryonic transcriptome), classic skeletal preparations (using dermestid beetles or alcian/alizarin), organ/embryo culture for pathway perturbation, field work to study the ecological context of morphology, classic dissection, Scientific Illustration, collaborations on kinematics/biomechanics of locomotion, phylogenetic reconstruction, mathematical modeling (collaborations). We are currently developed single cell RNA-seq in squamate embryonic skin to our lab’s research tool kit to better understand differentiation and cell fate. Natural History, Ecology and Husbandry and pivotal to our lab’s success as we need to truly understand animal care and biology to raise healthy animals that will breed in house. Reptiles are like family here!