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Reproductive mode and speciation: the viviparity‐driven conflict hypothesis
Author(s) -
Zeh David W.,
Zeh Jeanne A.
Publication year - 2000
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/1521-1878(200010)22:10<938::aid-bies9>3.0.co;2-9
Subject(s) - biology , reproductive isolation , evolutionary biology , coevolution , sexual conflict , genetic algorithm , hybrid zone , genetics , gene , sexual selection , genetic variation , gene flow , population , demography , sociology
In birds and frogs, species pairs retain the capacity to produce viable hybrids for tens of millions of years, an order of magnitude longer than mammals. What accounts for these differences in relative rates of pre‐ and postzygotic isolation? We propose that reproductive mode is a critically important but previously overlooked factor in the speciation process. Viviparity creates a post‐fertilization arena for genomic conflicts absent in egg‐laying species. With viviparity, conflict can arise between: mothers and embryos; sibling embryos in the womb, and maternal and paternal genomes within individual embryos. Such intra‐ and intergenomic conflicts result in perpetual antagonistic coevolution, thereby accelerating interpopulation postzygotic isolation. In addition, by generating intrapopulation genetic incompatibility, viviparity‐driven conflict favors polyandry and limits the potential for precopulatory divergence. Mammalian diversification is characterized by rapid evolution of incompatible feto‐maternal interactions, asymmetrical postzygotic isolation, disproportionate effects of genomically‐imprinted genes, and “F 2 hybrid enhancement.” The viviparity‐driven conflict hypothesis provides a parsimonious explanation for these patterns in mammalian evolution. BioEssays 22:938–946, 2000. © 2000 John Wiley & Sons, Inc.