Next weeks topic is Genomic Imprinting and Conflict, which relies heavily on insights of David Haig, an evolutionary theorist from Harvard.
David Haig writes:
“The most intimate human relationship is that between a mother and her unborn young. A fetus obtains all its nutrients and disposes of all of its wastes via its mother’s blood. It shares every breath that its mother takes, every meal she eats, and draws on her fat reserves when food is scarce. What is the nature of this relationship? Do mother and fetus form one body and one flesh, a harmonious union with each attentive to the other’s needs? Or is the fetus an alien intruder, a parasite that takes what it can without concern for its maternal host?
Neither the idyllic nor the parasitic vision adequately captures the complexities of pregnancy. Because they share half their genes, mother and fetus have common genetic interests, but sometimes their interests conflict because each also carries genes absent from the other. In particular, maternal and fetal genes are predicted to “disagree” over how a pregnant mother should allocate energy, time, and resources between her own needs and those of the fetus.”
(Reference: Prenatal power plays. By: Haig, David, Natural History, 00280712, Dec95, Vol. 104, Issue 12)
Since this is a long article, you can skim some sections but be sure to read the following sections carefully:
Genetic Conflict (p.497)
Fuel Supplies (p.510)
Putting up Resistance (p.513)
Pregnancy Induced Hypertension (p.515)
Birth and Beyond (p.516)
Haig D. Genetic Conflicts in Pregnancy. Quarterly Review of biology. Volume 68(4). Dec 1993, 495-532.
The Handout for Tuesday’s lecture is here:
WRITING PROJECT WILL BE DUE ON October 30th
Some have suggested that the age of weaning of infants from the breast is subject to parent offspring conflict. Since breastfeeding tends to suppress ovulation and delay pregnancy, do you think infants and mothers might have different optimum timing of weaning from breastfeeding? Give an evolutionary hypothesis for your answer. Do you think infants might exhibit behaviors that makes it hard for mothers to wean to solid food? What behaviors might these be? The infant has 1/2 maternal derived genes and 1/2 paternal derived genes; which of these would these be expected to prolong breastfeeding?