About

Dr. Christopher J. Percival is an Associate Professor in the Department of Anthropology at Stony Brook University. His research focuses on understanding the genetic and developmental bases of craniofacial phenotypes. Much of his current work involves the precise quantification of skull traits using 3D Computed Tomography images within experimental mouse models. This approach allows for detailed analysis of cranial morphology and the effects of genetic mutations on skull development. In addition to his research activities, Dr. Percival teaches courses in Human Anatomy, Human Genetics, and Bone Biology, contributing to the education of students in these fields.

Research topics

• Biology
• Computer Science
• Artificial Intelligence
• Genetics
• Cell biology
• Ecology
• Evolutionary biology
• Computer vision

Selected publications

• Allometry and Evolution of Neurocranial Narrowness Across Nonhuman Anthropoid Primates

  American Journal of Biological Anthropology · 2026-02-01

  articleOpen access

  OBJECTIVES: Among anthropoid primates, small-bodied platyrrhines exhibit striking mediolateral narrowness of the neurocranium relative to larger-bodied platyrrhines. Body size allometry has been hypothesized to explain variation in neurocranial narrowness. However, interspecific catarrhine variation appears inconsistent with the proposed platyrrhine allometry. This study tested the relationship between body size and neurocranial narrowness across anthropoids to identify whether clade-specific allometries have evolved. We further estimated neurocranial narrowness in anthropoid ancestors to determine the trait's evolutionary polarity. METHODS: Inter-clade shifts in degree and allometric scaling of neurocranial narrowness were identified with GLS pANCOVA, which combines generalized least-squares analysis (GLS) and phylogenetic analysis of covariance (pANCOVA). Ancestral trait estimation was performed using parsimony reconstruction methods, based on linear measurements of extant and fossil anthropoid skulls. RESULTS: In callitrichine and female cebine platyrrhines, neurocranial narrowness was significantly greater than predicted by body size and displayed a different allometric relationship than in other anthropoids. This shift is correlated with decreased neurocranial breadth in callitrichines, but not cebines. Neurocranial narrowness was not correlated with body size in most anthropoid clades. DISCUSSION: We did not identify a unified neurocranial narrowness allometry across platyrrhines or across anthropoids collectively. Nonetheless, reduced narrowness occurred parallel to the evolution of increased body size in catarrhines, atelids, and pitheciids, suggesting that larger body size may mitigate constraints on neurocranial shape responsible for narrow neurocrania in small-bodied fossil anthropoids, which have been retained only in small-bodied platyrrhines. Feeding adaptations and brain size also provide potential explanations for neurocranial narrowness variation in some clades.

  PublisherOA PDFDOI

• Neurocranial narrowness across nonhuman anthropoid primates

  Open MIND · 2026-02-02

  dataset

  Body size allometry has been proposed to explain neurocranial shape variation across platyrrhine monkeys, including the extreme neurocranial narrowness (NCN) of small-bodied taxa. However, catarrhine primates do not align with the proposed platyrrhine allometry, suggesting that body size alone may not explain anthropoid NCN variation. We measured NCN in platyrrhine and catarrhine anthropoids, and identified inter-clade differences in degree and allometric scaling of NCN using GLS pANCOVA, a method combining generalized least squares analysis and phylogenetic analysis of covariance. We further performed character history analysis using extant anthropoid data and fossil evidence to estimate neurocranial shape in anthropoid ancestors. We found no unified allometry of NCN across platyrrhines or across anthropoids as a whole, and there was no significant correlation between body mass and NCN across platyrrhines or catarrhines. At the subfamily level, callitrichine and possibly cebine platyrrhines differ from other anthropoids in degree and allometric scaling of NCN. Character history analysis suggests that higher NCN is the ancestral platyrrhine condition, and broader neurocranial shape evolved independently in catarrhines and larger-bodied platyrrhines. Our results support the hypothesis that body size does not explain anthropoid NCN variation, and provide a foundation for future research into potential correlates of anthropoid NCN.

  DOI

• Reduced Dietary Protein Induces Changes in the Dental Proteome

  Journal of Experimental Zoology Part B Molecular and Developmental Evolution · 2026-01-08

  articleOpen access

  Experimental studies have demonstrated that nutritional changes during development can result in phenotypic changes to mammalian cheek teeth. This developmental plasticity of tooth morphology is an example of phenotypic plasticity. Because tooth development occurs through complex interactions between manifold processes, there are many potential mechanisms which can contribute to a tooth's norm of reaction. Determining the identity of those mechanisms and the relative importance of each of them is one of the main challenges to understanding phenotypic plasticity. Quantitative proteomics combined with experimental studies allow for the identification of potential molecular contributors to a plastic response through quantification of expressed gene products. Here, we present the results of a quantitative proteomics analysis of mature upper first molars in Mus musculus from a controlled feeding experiment. Pregnant and nursing mothers were fed either a low-dietary protein (10%) treatment diet or control (20%) diet. Low-dietary protein was not associated with reduced molar size or skull length. However, expression of tooth-related proteins, immune system proteins, and actin-based myosin proteins were significantly altered in our low-dietary protein proteomics sample. The differential expression of immune proteins along with systematic reduction in actin-based myosin protein expression are novel discoveries for tooth proteomics studies. We propose that studies that aim to elucidate specific mechanisms of molar phenotypic plasticity should prioritize investigations into the relationships between IGF regulation and tooth development and actin-based myosin expression and tooth development.

  PublisherOA PDFDOI

• Evaluation of Nature-Based and Traditional Solutions for Urban Soil Decompaction

  Arboriculture & Urban Forestry · 2025-04-02 · 1 citations

  articleOpen access

  Abstract Background Urban forests play a significant role in mitigating the adverse effects of climate change by absorption of greenhouse gases and carbon sequestration. However, soil compaction caused by anthropogenic activities can be a major detriment to urban forest health. Method Two potential nature-based soil decompaction solutions (addition of earthworms, nitrogen-fixing white clover cropping) were evaluated in combination with existing soil decompaction systems (vertical mulching, woodchip surface layer). Effects on soil quality (bulk density, organic matter, pH, estimated nitrogen release, cotton strip degradation, and earthworm counts) and tree health (diameter at breast height [DBH], canopy density, root dry mass) were then monitored over 3 years. Results All decompaction treatments independently and in combination significantly reduced soil decompaction and improved tree growth with little difference recorded between treatments. Over time, however, earthworm populations migrated from the treated decompacted soil into the surrounding untreated compacted soil, in turn, significantly improving soil quality allowing for enhanced root growth outside the treated area. Conclusion A long-term, sustainable, nature-based solution exists for professionals involved in urban tree management to improve compacted soil quality and subsequent tree health.

  PublisherOA PDFDOI

• Palatal segment contributions to midfacial anterior–posterior growth

  Journal of Anatomy · 2025-01-20 · 3 citations

  articleOpen accessSenior authorCorresponding

  Anterior-posterior (A-P) elongation of the palate is a critical aspect of integrated midfacial morphogenesis. Reciprocal epithelial-mesenchymal interactions drive secondary palate elongation that is coupled to the periodic formation of signaling centers within the rugae growth zone (RGZ). However, the relationship between RGZ-driven morphogenetic processes, the differentiative dynamics of underlying palatal bone mesenchymal precursors, and the segmental organization of the upper jaw has remained enigmatic. A detailed ontogenetic study of these relationships is important because palatal segment growth is a critical aspect of normal midfacial growth, can produce dysmorphology when altered, and is a likely basis for evolutionary differences in upper jaw morphology. We completed a combined whole mount gene expression and morphometric analysis of normal murine palatal segment growth dynamics and resulting upper jaw morphology. Our results demonstrated that the first formed palatal ruga (ruga 1), found just posterior to the RGZ, maintained an association with important nasal, neurovascular and palatal structures throughout early midfacial development. This suggested that these features are positioned at a proximal source of embryonic midfacial directional growth. Our detailed characterization of midfacial morphogenesis revealed a one-to-one relationship between palatal segments and upper jaw bones during the earliest stages of palatal elongation. Growth of the maxillary anlage within the anterior secondary palate is uniquely coupled to RGZ-driven morphogenesis. This may help drive the unequaled proportional elongation of the anterior secondary palate segment prior to palatal shelf fusion. Our results also demonstrated that the future maxillary-palatine suture, approximated by the position of ruga 1 and consistently associated with the palatine anlage, formed predominantly via the posterior differentiation of the maxilla within the expanding anterior secondary palate. Our ontogenetic analysis provides a novel and detailed picture of the earliest spatiotemporal dynamics of intramembranous midfacial skeletal specification and differentiation within the context of the surrounding palatal segment A-P elongation and associated rugae formation.

  PublisherOA PDFDOI

• Reduced Dietary Protein Induces Changes in the Dental Proteome

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-01-13

  preprintOpen access

  Abstract Experimental studies have demonstrated that nutritional changes during development can result in phenotypic changes to mammalian cheek teeth. This developmental plasticity of tooth morphology is an example of phenotypic plasticity. Because tooth development occurs through complex interactions between manifold processes, there are many potential mechanisms which can contribute to a tooth’s norm of reaction. Determining the identity of those mechanisms and the relative importance of each of them is one of the main challenges to understanding phenotypic plasticity. Quantitative proteomics combined with experimental studies allow for the identification of potential molecular contributors to a plastic response through quantification of expressed gene products. Here, we present the results of a quantitative proteomics analysis of mature upper first molars in Mus musculus from a controlled feeding experiment. Pregnant and nursing mothers were fed either a low-dietary protein (10%) treatment diet or control (20%) diet. Low-dietary protein was not associated with reduced molar size or skull length. However, expression of tooth-related proteins, immune system proteins, and actin-based myosin proteins were significantly altered in our low-dietary protein proteomics sample. The differential expression of immune proteins along with systematic reduction in actin-based myosin protein expression are novel discoveries for tooth proteomics studies. We propose that studies that aim to elucidate specific mechanisms of molar phenotypic plasticity should prioritize investigations into the relationships between IGF regulation and tooth development and actin-based myosin expression and tooth development. Research Highlights A low-protein diet during development results in significantly altered protein expression for odontogenetic and osteogenic proteins, immune system proteins, and actin-based myosin proteins within Mus musculus , but does not alter skull length or molar size. Graphical Abstract

  PublisherOA PDFDOI

• Genetic architecture of trait variance in craniofacial morphology

  Genetics · 2024-02-22

  articleOpen access

  The genetic architecture of trait variance has long been of interest in genetics and evolution. One of the earliest attempts to understand this architecture was presented in Lerner's Genetic Homeostasis (1954). Lerner proposed that heterozygotes should be better able to tolerate environmental perturbations because of functional differences between the alleles at a given locus, with each allele optimal for slightly different environments. This greater robustness to environmental variance, he argued, would result in smaller trait variance for heterozygotes. The evidence for Lerner's hypothesis has been inconclusive. To address this question using modern genomic methods, we mapped loci associated with differences in trait variance (vQTL) on 1,101 individuals from the F34 of an advanced intercross between LG/J and SM/J mice. We also mapped epistatic interactions for these vQTL in order to understand the influence of epistasis for the architecture of trait variance. We did not find evidence supporting Lerner's hypothesis, that heterozygotes tend to have smaller trait variances than homozygotes. We further show that the effects of most mapped loci on trait variance are produced by epistasis affecting trait means and that those epistatic effects account for about a half of the differences in genotypic-specific trait variances. Finally, we propose a model where the different interactions between the additive and dominance effects of the vQTL and their epistatic partners can explain Lerner's original observations but can also be extended to include other conditions where heterozygotes are not the least variable genotype.

  PublisherOA PDFDOI

• Review for "What is a trait? Lessons from the human chin"

  2024-02-01

  peer-review1st authorCorresponding
  PublisherDOI

• Author Correction: MusMorph, a database of standardized mouse morphology data for morphometric meta-analyses

  Scientific Data · 2023-06-28 · 1 citations

  erratumOpen access

  Correction to: Scientific Data, published online 25 May 2022 The order of the column headings was incorrect in Table 1, meaning values were listed under the wrong descriptions. This has been corrected in the pdf and HTML versions of the article.

  PublisherOA PDFDOI

• The Influence of Chitin- and Chitosan-Based Soil Amendments on Pathogen Severity of Apple and Pear Scab

  Arboriculture & Urban Forestry · 2023-03-01 · 3 citations

  articleOpen access

  Apple and pear scab are foliar pathogens of apple and pear trees. Unmanaged, yield and aesthetic losses can be severe. The risk of resistance associated with over-reliance on fungicides means novel pathogen management methods and products are increasingly required. Chitin and chitosan are widely recognised as induced resistance (IR) agents that trigger plant defence responses that in turn enhance plant resilience to pathogen ingress. A container and field trial was conducted using apple (Malus sylvestris) and pear (Pyrus communis ‘Conference’) respectively to assess the efficacy of a range of liquid and granular chitin/chitosan-based IR agents and fertilisers against apple and pear scab. A synthetic fungicide (penconazole) spray program used within the UK for apple and pear scab control was included for comparison. Application of chitin/chitosan IR agents at concentrations above 1% caused phytotoxicity. Limited efficacy as scab protectants was also demonstrated when chitin/chitosan IR agents were applied at concentrations of 0.25%. However, chitin IR agents when applied at 0.5% and 1% and chitosan IR agents at 1% demonstrated efficacy as scab protectants and resulted in an increased leaf chlorophyll content, increased fruit yield, and reduced leaf scab severity when compared against the watered control. Only one of three chitin/chitosan fertilisers evaluated demonstrated efficacy as scab protectants (liquid chitosan). A synthetic fungicide penconazole spray program provided the greatest protection against apple and pear scab in the container trials. However, under field conditions the degree of scab control following application of chitin and chitosan at 1% and the chitosan containing fertiliser liquid chitosan was statistically comparable to fungicide treated trees. Results suggest application of an appropriate chitin/chitosan IR agent(s) and fertiliser offers a useful addition to existing methods of apple and pear scab management under field and container conditions.

  PublisherOA PDFDOI

Frequent coauthors

• Benedikt Hallgrímsson

  Alberta Children's Hospital

  80 shared

• Ralph Marcucio

  University of California, San Francisco

  29 shared

• Rebecca M. Green

  Statistics New Zealand

  24 shared

• Terrence Ritzman

  Midwestern University

  21 shared

• Charles C. Roseman

  University of Illinois Urbana-Champaign

  21 shared

• Joan T. Richtsmeier

  19 shared

• Ethylin Wang Jabs

  Mayo Clinic in Florida

  15 shared

• R. Ackermann

  14 shared

Labs

• Percival LabPI

Education

• PhD, Anthropology

  Pennsylvania State University University Park

  2013

• BS, Anthropology

  Rutgers University New Brunswick

  2006