Heritability of fearful-anxious endophenotypes in infant rhesus macaques: a preliminary report.
BACKGROUND
Research efforts to discover the genetic underpinnings of anxiety and depression is challenging because of the etiologic heterogeneity inherent to these disorders. These efforts might be aided by the study of related behavioral phenotypes in model organisms, such as monkeys.


METHODS
Eighty-five rhesus monkeys (Macaca mulatta) from the Oregon National Primate Research Center were drawn from a standard matriarchal colony and tested for behavioral response in four testing paradigms designed to elicit fearful-anxious reactions. Heritabilities were estimated using variance component-based quantitative genetic analyses with much of the genetic information arising from paternal half-sibs.


RESULTS
Individual behaviors reflecting increased distress responses (e.g., vocalizations and teeth grinding) and behavioral inhibition (e.g., latency to leave mother, latency to inspect novel fruit) showed significant heritability, even though a small number of monkeys were assessed. Exploratory factor analyses identified seven clusters of behaviors across tests, some of which were found to be heritable.


CONCLUSIONS
These results indicate that several specific fearful-anxious behaviors in infant rhesus monkeys are heritable within this colony. Accordingly, these phenotypes, which are believed to represent the genetic liability for anxiety and depression, are good candidates for further genetic investigation in this population.
Williamson
Douglas E
DE
Department of Psychiatry, University of Pittsburgh Medical Center, Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania 15213, USA.
Coleman
Kris
K
Bacanu
Silviu-Alin
SA
Devlin
Bernie J
BJ
Rogers
Jeffrey
J
Ryan
Neal D
ND
Cameron
Judy L
JL
D000818:Animals; D001007:Anxiety / Q000235:genetics*; D001522:Behavior, Animal / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D004569:Electroencephalography; D005163:Factor Analysis, Statistical; D005239:Fear / Q000502:physiology*; D005260:Female; D008253:Macaca mulatta; D008297:Male; D010641:Phenotype; D014828:Vocalization, Animal / Q000502:physiology
D003346:Corticotropin-Releasing Hormone