Abstract # 13068 Event # 124:

Scheduled for Friday, August 10, 2018 11:30 AM-11:45 AM: (Chula Vista ) Oral Presentation


MECHANISM AT LARGE: SIBLING SEX, BUT NOT ANDROGENS, INFLUENCES PHENOTYPES IN PERINATAL COMMON MARMOSETS (CALLITHRIX JACCHUS)

 

B. M. Frye1, L. G. Rapaport1, T. Melber2, M. W. Sears1 and S. D. Tardif3
1Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, USA, 2Department of Anthropology, University of Illinois, Urbana, 3Southwest National Primate Research Center
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When offspring share a womb, as in callitrichines, interactions between fetuses could impart lasting impressions on phenotypic outcomes. Such interactions might be mediated, in part, by sex steroids (estrogens and androgens) produced by the fetuses themselves. Here, we used an array of physiological, morphological, and behavioral assays to investigate whether the sex composition of litters influences perinatal outcomes in common marmosets (Callithrix jacchus). We hypothesized that androgens from male fetuses would mediate developmental differences across litters. Our overall sample consisted of 202 twin and triplet infants born into same-sex (SS) (NmaleSS=25; NfemaleSS=40) and mixed-sex (MS) litters (NmaleMS=70; NfemaleMS=67) at the Southwest National Primate Research Center. Generally, newborns (24 - 36 hours old) from same- and mixed-sex litters were indistinguishable. That is, generalized linear mixed models did not reveal any differences in androgen profiles (t= -0.320, p=0.748), birth weights (t=1.362, p=0.175), morphometrics (p>0.05), and behavior (cumulative link mixed models: p>0.05). However, monkeys born into same- and mixed-sex litters exhibited differences later in the perinatal period. Marmosets from same-sex litters were heavier than those from mixed-sex litters (GLMM: t=2.386; p=0.018). Same-sex infants also exhibited distinct behavior profiles on days 15 and 30 (CLMMs: p<0.05). This work rejects our hypothesis that androgens from male fetuses mediate development. Future investigations should examine how familial interactions might vary with the sex composition of litters, especially during the perinatal period.