Placental invasiveness and brain-body allometry in eutherian mammals

M. G. Elliot*, B. J. Crespi

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

29 Citations (Scopus)

Abstract

Brain growth is a key trait in the evolution of mammalian life history. Brain development should be mediated by placentation, which determines patterns of resource transfer from mothers to fetal offspring. Eutherian placentation varies in the extent to which a maternal barrier separates fetal tissues from maternal blood. We demonstrate here that more invasive forms of placentation are associated with substantially steeper brain-body allometry, faster prenatal brain growth and slower prenatal body growth. On the basis of the physiological literature we suggest a simple mechanism for these differences: in species with invasive placentation, where the placenta is bathed directly in maternal blood, fatty acids essential for brain development can be readily extracted by the fetus, but in species with less invasive placentation they must be synthesized by the fetus. Hence, with regard to brain-body allometry and prenatal growth patterns, eutherian mammals are structured into distinct groups differing in placental invasiveness.

Original languageEnglish
Pages (from-to)1763-1778
Number of pages16
JournalJournal of Evolutionary Biology
Volume21
Issue number6
DOIs
Publication statusPublished - Nov-2008
Externally publishedYes

Keywords

  • brain size
  • encephalization
  • Eutheria
  • evolution
  • fatty acids
  • fetal nutrition
  • life history
  • placentation
  • pregnancy
  • FREE FATTY-ACIDS
  • EXPENSIVE-TISSUE HYPOTHESIS
  • MATERNO-FETAL EXCHANGES
  • NEOCORTEX SIZE
  • BEHAVIORAL ECOLOGY
  • RABBIT PLACENTA
  • LATE-GESTATION
  • GUINEA-PIG
  • LINOLEIC ACIDS
  • SOCIAL BRAIN

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