TY - JOUR
T1 - Primate enamel evinces long period biological timing and regulation of life history
AU - Bromage, Timothy G.
AU - Hogg, Russell T.
AU - Lacruz, Rodrigo S.
AU - Hou, Chen
N1 - Funding Information:
Research support was provided by the 2010 Max Planck Research Award to TGB, endowed by the German Federal Ministry of Education and Research to the Max Planck Society and the Alexander von Humboldt Foundation in respect of the Hard Tissue Research Program in Human Paleobiomics. Aspects of this study were also supported by National Science Foundation grants in aid of research to TGB ( BCS-1062680 ) and RTH ( BCS-0622479 ) and by the L.S.B. Leakey Foundation, the Palaeo-Anthropological Scientific Trust, and D. McSherry to RSL and TGB. Additional support to TGB was provided by the New York University Health Sciences Libraries. The work reported here benefited greatly from discussions with Jim Brown of the University of New Mexico, Mal Janal of the New York University College of Dentistry, David Weaver of the University of Massachusetts Medical School, and several enthusiastic anonymous reviewers.
PY - 2012/7/21
Y1 - 2012/7/21
N2 - The factor(s) regulating the combination of traits that define the overall life history matrix of mammalian species, comprising attributes such as brain and body weight, age at sexual maturity, lifespan and others, remains a complete mystery. The principal objectives of the present research are (1) to provide evidence for a key variable effecting life history integration and (2) to provide a model for how one would go about investigating the metabolic mechanisms responsible for this rhythm. We suggest here that a biological rhythm with a period greater than the circadian rhythm is responsible for observed variation in primate life history. Evidence for this rhythm derives from studies of tooth enamel formation. Enamel contains an enigmatic periodicity in its microstructure called the striae of Retzius, which develops at species specific intervals in units of whole days. We refer to this enamel rhythm as the repeat interval (RI). For primates, we identify statistically significant relationships between RI and all common life history traits. Importantly, RI also correlates with basal and specific metabolic rates. With the exception of estrous cyclicity, all relationships share a dependence upon body mass. This dependence on body mass informs us that some aspect of metabolism is responsible for periodic energy allocations at RI timescales, regulating cell proliferation rates and growth, thus controlling the pace, patterning, and co-variation of life history traits. Estrous cyclicity relates to the long period rhythm in a body mass-independent manner. The mass-dependency and -independency of life history relationships with RI periodicity align with hypothalamic-mediated neurosecretory anterior and posterior pituitary outputs. We term this period the Havers-Halberg Oscillation (HHO), in reference to Clopton Havers, a 17th Century hard tissue anatomist, and Franz Halberg, a long-time explorer of long-period rhythms. We propose a mathematical model that may help elucidate the underlying physiological mechanism responsible for the HHO.
AB - The factor(s) regulating the combination of traits that define the overall life history matrix of mammalian species, comprising attributes such as brain and body weight, age at sexual maturity, lifespan and others, remains a complete mystery. The principal objectives of the present research are (1) to provide evidence for a key variable effecting life history integration and (2) to provide a model for how one would go about investigating the metabolic mechanisms responsible for this rhythm. We suggest here that a biological rhythm with a period greater than the circadian rhythm is responsible for observed variation in primate life history. Evidence for this rhythm derives from studies of tooth enamel formation. Enamel contains an enigmatic periodicity in its microstructure called the striae of Retzius, which develops at species specific intervals in units of whole days. We refer to this enamel rhythm as the repeat interval (RI). For primates, we identify statistically significant relationships between RI and all common life history traits. Importantly, RI also correlates with basal and specific metabolic rates. With the exception of estrous cyclicity, all relationships share a dependence upon body mass. This dependence on body mass informs us that some aspect of metabolism is responsible for periodic energy allocations at RI timescales, regulating cell proliferation rates and growth, thus controlling the pace, patterning, and co-variation of life history traits. Estrous cyclicity relates to the long period rhythm in a body mass-independent manner. The mass-dependency and -independency of life history relationships with RI periodicity align with hypothalamic-mediated neurosecretory anterior and posterior pituitary outputs. We term this period the Havers-Halberg Oscillation (HHO), in reference to Clopton Havers, a 17th Century hard tissue anatomist, and Franz Halberg, a long-time explorer of long-period rhythms. We propose a mathematical model that may help elucidate the underlying physiological mechanism responsible for the HHO.
KW - Cell proliferation
KW - Enamel striae of retzius
KW - Hypothalamic-pituitary axis
KW - Long period biological rhythm
KW - Metabolism
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U2 - 10.1016/j.jtbi.2012.04.007
DO - 10.1016/j.jtbi.2012.04.007
M3 - Article
C2 - 22542323
AN - SCOPUS:84860600202
SN - 0022-5193
VL - 305
SP - 131
EP - 144
JO - Journal of Theoretical Biology
JF - Journal of Theoretical Biology
ER -