Research - Bone Development

Bone is a highly dynamic tissue that is under constant reconstruction. It functions to support and protect our soft tissue as well as to store essential minerals such as calcium and phosphorus. It is both tough and flexible allowing it to resist both compression (as in the leg of a race horse) and torsion (as in the wing of a dove). The plasticity of bone development allows for microstructural form to support and reflective function of individual skeletal elements. Bone's intimate link to physiology dictates that annual changes in metabolic rate and physiological stresses such as disease, deprivation and reproduction can also be reflected in bone microstructure. It is these landmarks of function and physiology found in bone microstructure that our group is studying. Currently our research is focusing on the following four questions:

1) Is bone formed in a cyclical pattern? Researchers have found evidence that in many species bone is laid down in an annual cyclical pattern. Microstructural signatures such as lines of arrested growth (LAGs), annuli and growth-layer-groups (GLGs) have been used with varying success to measure age (a method known as skeletochronology) in a wide variety of taxa including bony fish, amphibians, some reptiles and a few mammals. We will examine the bone of additional taxa to determine how widespread such "annual" signatures are and if they are in fact formed annually.
What effect, if any, does hibernation have on bone formation and maintenance? In many species extended periods of disuse result in disuse osteopenia (a decrease in bone mass). However, some species, despite spending many months in hibernation, are able to avoid osteopenia. We will be examining which species are able to maintain bone mass despite disuse and which species a forced to rebuild bone after hibernation. We will also be looking for signatures in the microstructure of hibernating animals to determine if it is possible to predict whether or not an animal did hibernate and if so, how long it hibernated for.
What effect, if any, does reproduction have on bone formation and maintenance? This question is most pertinent to mammal species in which females must provide a great deal of calcium and phosphorus to their offspring during pregnancy and nursing. We will be looking for signatures in the bone microstructure of mammal species to determine if there is a morphological dimorphism based on whether or not an organism was reproductive or not.
To what extent is the function of a skeletal element reflected in its microstructure patterns? Are there different microstructural patterns depending on whether an organism is swimming, flying or running? Previous studies have suggested that there is. We will attempt to more fully understand how form and function are related in the microstructure of vertebrate limb bones.

Ultimately, by moving towards answering the four questions posed above we hope to be able to use our findings to more fully understand the patterns in bone microstructure that we are seeing the fossil record.

Student Researchers: Maria de Boef




Bone Development		Bone is a highly dynamic tissue that is under constant reconstruction. It functions to support and protect our soft tissue as well as to store essential minerals such as calcium and phosphorus. It is both tough and flexible allowing it to resist both compression (as in the leg of a race horse) and torsion (as in the wing of a dove). The plasticity of bone development allows for microstructural form to support and reflective function of individual skeletal elements. Bone's intimate link to physiology dictates that annual changes in metabolic rate and physiological stresses such as disease, deprivation and reproduction can also be reflected in bone microstructure. It is these landmarks of function and physiology found in bone microstructure that our group is studying. Currently our research is focusing on the following four questions: 1) Is bone formed in a cyclical pattern? Researchers have found evidence that in many species bone is laid down in an annual cyclical pattern. Microstructural signatures such as lines of arrested growth (LAGs), annuli and growth-layer-groups (GLGs) have been used with varying success to measure age (a method known as skeletochronology) in a wide variety of taxa including bony fish, amphibians, some reptiles and a few mammals. We will examine the bone of additional taxa to determine how widespread such "annual" signatures are and if they are in fact formed annually. What effect, if any, does hibernation have on bone formation and maintenance? In many species extended periods of disuse result in disuse osteopenia (a decrease in bone mass). However, some species, despite spending many months in hibernation, are able to avoid osteopenia. We will be examining which species are able to maintain bone mass despite disuse and which species a forced to rebuild bone after hibernation. We will also be looking for signatures in the microstructure of hibernating animals to determine if it is possible to predict whether or not an animal did hibernate and if so, how long it hibernated for. What effect, if any, does reproduction have on bone formation and maintenance? This question is most pertinent to mammal species in which females must provide a great deal of calcium and phosphorus to their offspring during pregnancy and nursing. We will be looking for signatures in the bone microstructure of mammal species to determine if there is a morphological dimorphism based on whether or not an organism was reproductive or not. To what extent is the function of a skeletal element reflected in its microstructure patterns? Are there different microstructural patterns depending on whether an organism is swimming, flying or running? Previous studies have suggested that there is. We will attempt to more fully understand how form and function are related in the microstructure of vertebrate limb bones. Ultimately, by moving towards answering the four questions posed above we hope to be able to use our findings to more fully understand the patterns in bone microstructure that we are seeing the fossil record. Student Researchers: Maria de Boef