ALTERCATION OF GENERATIONS - GENETIC CONFLICTS OF PREGNANCY

Pregnancy is traditionally viewed as a harmonious collaboration betwee n mother and fetus. From this perspective, viviparity poses a series o f problems that maternal and fetal genes work together to solve and th e many complications of pregnancy are interpreted as evidence of the m alfunctioning of an evolved system or of the failure of natural select ion to achieve an adaptive goal. This view fails to recognize aspects of genetic conflict that lie at the heart of gestation. At least three interrelated sources of conflict can be identified: (i) conflict betw een genes expressed in the mother and genes expressed in the fetus/pla centa (parent-offspring conflict); (ii) conflict between maternally-de rived and paternally-derived genes within the fetal genome (genomic im printing); and (iii) conflict between maternal genes that recognize th emselves in offspring and the rest of the maternal genome (gestational drive).