About

Christopher Walker is an assistant professor at the College of Veterinary Medicine, specializing in anatomy and biological anthropology. His research focuses on hominin paleontology, growth and development, functional morphology of the postcranial skeleton, mobility, and anatomical variation. The primary goal of his research is to elucidate the adaptive significance of changes to locomotor anatomy during hominin evolution, aiming to understand how hominins moved throughout their environment and what prompted shifts in their bony anatomy. His teaching expertise includes mammalian anatomy, covering gross anatomy, osteology, and functional morphology. Walker holds a PhD in Evolutionary Anthropology from Duke University, an MPhil in Biological Anthropological Science from the University of Cambridge, and a BA in Biological Anthropology from the University of California. His work contributes to understanding evolutionary and biomedical implications of anatomical variations and adaptations in hominin species.

Research topics

• Biology
• Psychology
• Evolutionary biology
• Neuroscience
• Medicine
• Genetics
• Cognitive psychology
• Archaeology
• Pathology
• Immunology
• Geology
• Geography
• Paleontology
• Social psychology
• Developmental psychology

Selected publications

• Age and early life adversity shape heterogeneity of the epigenome across tissues in macaques

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-07-18 · 1 citations

  preprintOpen access

  Age and early life adversity (ELA) are both key determinants of health, but whether they target similar physiological mechanisms across the body is unknown due to limited multi-tissue datasets from well-characterized cohorts. We generated DNA methylation (DNAm) profiles across 14 tissues in 237 semi-free ranging rhesus macaques, with records of naturally occurring ELA. We show that age-associated DNAm variation is predominantly tissue-dependent, yet tissue-specific epigenetic clocks reveal that the pace of epigenetic aging is relatively consistent within individuals. ELA effects on loci are adversity-dependent, but a given ELA has a coordinated impact across tissues. Finally, ELA targeted many of the same loci as age, but the direction of these effects varied, indicating that ELA does not uniformly contribute to accelerated age in the epigenome. ELA thus imprints a coordinated, tissue-spanning epigenetic signature that is both distinct from and intertwined with age-related change, advancing our understanding of how early environments sculpt the molecular foundations of aging and disease.

  PublisherOA PDFDOI

• Long legs and small joints: The locomotor capabilities of <i>Homo naledi</i>

  Journal of Anatomy · 2025-01-21

  articleOpen access

  The lower limb of Homo naledi presents a suite of primitive, derived and unique morphological features that pose interesting questions about the nature of bipedal movement in this species. The exceptional representation of all skeletal elements in H. naledi makes it an excellent candidate for biomechanical analysis of gait dynamics using modern kinematic software. However, virtual gait analysis software requires 3D models of the entire lower limb kinematic chain. No single H. naledi individual preserves all lower limb elements, and what material is preserved is fragmentary. As an antecedent to future kinematic analysis, a 3D lower limb skeleton was reconstructed from the most complete fossil bones of different H. naledi individuals. As both juvenile and adult H. naledi were used, we tested if the knee joint remained congruent throughout ontogeny in a sample of great apes (N = 143) and modern humans (N = 70). The reconstruction and subsequent comparative analysis reveal that H. naledi had remarkably small joint sizes for their body size, a hyper-elongated tibia, and a high crural index (90.2). We consider that the lower limb morphology of H. naledi could have improved locomotor economy, but the exceptionally small joints cast doubt on its capabilities for long distance travel, including endurance running. The unusual mixture of primitive and derived traits in H. naledi remains intriguing and might indicate that this hominin engaged both in bipedal walking and climbing, demonstrating that kinematic diversity in hominins persisted well into the Middle Pleistocene.

  PublisherOA PDFDOI

• Evolutionary and biomedical implications of sex differences in the primate brain transcriptome

  Cell Genomics · 2024-06-27 · 18 citations

  articleOpen access

  Humans exhibit sex differences in the prevalence of many neurodevelopmental disorders and neurodegenerative diseases. Here, we generated one of the largest multi-brain-region bulk transcriptional datasets for the rhesus macaque and characterized sex-biased gene expression patterns to investigate the translatability of this species for sex-biased neurological conditions. We identify patterns similar to those in humans, which are associated with overlapping regulatory mechanisms, biological processes, and genes implicated in sex-biased human disorders, including autism. We also show that sex-biased genes exhibit greater genetic variance for expression and more tissue-specific expression patterns, which may facilitate rapid evolution of sex-biased genes. Our findings provide insights into the biological mechanisms underlying sex-biased disease and support the rhesus macaque model for the translational study of these conditions.

  PublisherDOI

• Social connections predict brain structure in a multidimensional free-ranging primate society

  Science Advances · 2022 · 62 citations

  • Psychology
  • Neuroscience
  • Developmental psychology

  Reproduction and survival in most primate species reflects management of both competitive and cooperative relationships. Here, we investigated the links between neuroanatomy and sociality in free-ranging rhesus macaques. In adults, the number of social partners predicted the volume of the mid-superior temporal sulcus and ventral-dysgranular insula, implicated in social decision-making and empathy, respectively. We found no link between brain structure and other key social variables such as social status or indirect connectedness in adults, nor between maternal social networks or status and dependent infant brain structure. Our findings demonstrate that the size of specific brain structures varies with the number of direct affiliative social connections and suggest that this relationship may arise during development. These results reinforce proposed links between social network size, biological success, and the expansion of specific brain circuits.

  PublisherOA PDFDOI

• The immature <i>Homo naledi</i> ilium from the Lesedi Chamber, Rising Star Cave, South Africa

  American Journal of Biological Anthropology · 2022-04-16 · 8 citations

  articleOpen access

  Abstract Objectives Homo naledi is represented by abundant remains from the Dinaledi Chamber of the Rising Star Cave system in South Africa. While pelvic elements from the Dinaledi Chamber of the cave are fragmentary, a relatively complete ilium (U.W. 102a–138) was recovered from the Lesedi Chamber. We reconstructed and analyzed the Lesedi ilium, providing qualitative descriptions and quantitative assessment of its morphology and developmental state. Materials and Methods We compared the Lesedi ilium to remains from the Dinaledi Chamber, other South African hominin fossils, and an ontogenetic series of human ilia. We used the Dinaledi adults as a guide for reconstructing the Lesedi ilium. To assess development of the Lesedi ilium, we compared immature/mature proportional ilium height for fossils and humans. We used 3D geometric morphometrics (GMs) to examine size and shape variation among this sample. Results The Lesedi ilium showed incipient development of features expressed in adult H. naledi ilia. The proportional height of the Lesedi ilium was within the range of human juveniles between 4–11 years of age. GM analyses showed that the Lesedi ilium had an iliac blade shape similar to those of australopiths and an expanded auricular surface more similar to humans. Conclusions The reconstructed Lesedi specimen represents the best preserved ilium of H. naledi , confirming the australopith‐like iliac blade morphology first hypothesized in adult specimens, and establishing that this anatomy was present early in this species' ontogeny. In contrast to australopiths, the Lesedi ilium displays an enlarged sacroiliac joint, the significance of which requires further investigation.

  PublisherDOI

• Evolutionary and biomedical implications of sex differences in the primate brain transcriptome

  bioRxiv (Cold Spring Harbor Laboratory) · 2022-10-04 · 5 citations

  preprintOpen access

  Humans exhibit sex differences in the prevalence of many neurodevelopmental and neurodegenerative conditions. To better understand the translatability of a critical nonhuman primate model, the rhesus macaque, we generated one of the largest multibrain region bulk transcriptional datasets for this species and characterized sex-biased gene expression patterns. We demonstrate that these patterns are similar to those in humans and are associated with overlapping regulatory mechanisms, biological processes, and genes implicated in sex-biased human disorders, including autism. We also show that sex-biased genes exhibit greater genetic variance for expression and more tissue-specific expression patterns, which may facilitate the rapid evolution of sex-biased genes. Our findings provide insights into the biological mechanisms underlying sex-biased disease and validate the rhesus macaque model for the study of these conditions.

  PublisherOA PDFDOI

• Multiregion transcriptomic profiling of the primate brain reveals signatures of aging and the social environment

  Nature Neuroscience · 2022 · 34 citations

  • Neuroscience
  • Biology
  • Psychology
  PublisherOA PDFDOI

• Evaluating bony predictors of bite force across the order <scp>Carnivora</scp>

  Journal of Morphology · 2021-07-27 · 15 citations

  article

  In carnivorans, bite force is a critical and ecologically informative variable that has been correlated with multiple morphological, behavioral, and environmental attributes. Whereas in vivo measures of biting performance are difficult to obtain in many taxa-and impossible in extinct species-numerous osteological proxies exist for estimating masticatory muscle size and force. These proxies include both volumetric approximations of muscle dimensions and direct measurements of muscular attachment sites. In this study, we compare three cranial osteological techniques for estimating muscle size (including 2D-photographic and 3D-surface data approaches) against dissection-derived muscle weights and physiological cross-sectional area (PCSA) within the jaw adductor musculature of 40 carnivoran taxa spanning eight families, four orders of magnitude in body size, and the full dietary spectrum of the order. Our results indicate that 3D-approaches provide more accurate estimates of muscle size than do surfaces measured from 2D-lateral photographs. However, estimates of a muscle's maximum cross-sectional area are more closely correlated with muscle mass and PCSA than any estimates derived from muscle attachment areas. These findings highlight the importance of accounting for muscle thickness in osteological estimations of the masticatory musculature; as muscles become volumetrically larger, their larger cross-sectional area does not appear to be associated with a proportional increase in the attachment site area. Though volumetric approaches approximate muscle dimensions well across the order as a whole, caution should be exercised when applying any single method as a predictor across diverse phylogenies.

  PublisherDOI

• Author response for "Evaluating bony predictors of bite force across the order Carnivora"

  2021-06-30

  peer-reviewOpen access
  PublisherDOI

• Internal structural properties of the humeral diaphyses in an early modern human from Tianyuan Cave, China

  Quaternary International · 2021-04-19 · 11 citations

  article
  PublisherDOI

Frequent coauthors

• Steven E. Churchill

  Duke University

  64 shared

• John Hawks

  University of the Witwatersrand

  39 shared

• Jeremy M. DeSilva

  Dartmouth College

  35 shared

• Lee R. Berger

  University of the Witwatersrand

  27 shared

• Damiano Marchi

  University of Pisa

  26 shared

• Zachary Cofran

  24 shared

• Gabriel Yapuncich

  Duke University

  23 shared

• Scott A. Williams

  United Nations Economic and Social Commission for Asia and the Pacific

  23 shared

Education

• PhD, Evolutionary Anthropology

  Duke University