Growth hormone

1
A gentle immunological balance thus has to be
maintained in the decidua, where immunological
activity operates to eliminate a pathogen without
damaging the fetus
Markel et al. (2002)Journal of Clinical
Investigation 110 943
2
The border zone is not a sharp line, for it is
in truth the fighting line where the conflict
between the maternal cells and the invading
trophoderm takes place, and it is strewn with
such of the dead on both sides as have not
already been carried off the field or otherwise
disposed of.
Johnstone (May 1914) Journal of Obstetrics and
Gynaecology of the British Empire 25 231
3
Maternal provisioning of a fetus is associated
with an opportunity cost
The opportunity cost translates into lower
expected fitness through other offspring
4
If extra resources are transferred to an embryo

• the embryos expected fitness increases
• the mothers expected fitness from other
  offspring decreases

5
maternal investment in fetus
6
X
X minimizes cost to siblings
7
X
Z
Z maximizes benefit to fetus
8
cost
cost to siblings
X
Z
Y
Y maximizes (benefit cost)
9
mother
maternal (non-inherited)
maternal(inherited)
paternal(inherited)
fetus
10
Relative shares
Benefit (to fetus)
Cost (to sibs)
gene
p probability of shared paternity
11
A non-inherited maternal gene gains no benefit
from the survival and reproduction of a fetus
12
worse than that!
13
Non-inherited maternal genes will benefit from
the early demise of the fetus
14
How is pregnancy possible?

• rarity of genetic self-recognition
• the parliament of the genes(mutual policing)

15
Paternally-derived genes in fetuses favor greater
demands on mothers than maternally-derived genes
16
(No Transcript)
17
fetus
yolk sac
trophoblast
mum dad
mum mum
dad dad
18
46,XX paternal origin

• massively proliferating placental tissues
• 1,000-fold increased risk of choriocarcinoma

19
46,XX maternal origin

• ovarian teratomas benign
• produce most tissues (but not placenta)

20
mother
maternal (non-inherited)
maternal(inherited)
paternal(inherited)
fetus
21
incomplete information
Benefit (to fetus)
Cost (to sibs)
p probability of shared paternity
22
(No Transcript)
23
spiral artery
umbilical cord
uterine vein
24
Conflict can exist over

• whether or not to miscarry
• the nutrient quality of maternal blood
• the volume of blood reaching the placenta

25
ovulation (day 0)
hCG (day 7)
CL regresses (days 8-10)
onset of menstruation (day 14)
26
women attempting to conceive

• number of cycles
• chemical pregnancies
• clinical pregnancies
• term pregnancies

• 707
• 198
• 155
• 136

data from Wilcox et al. (1988)
27
anterior pituitary
corpus luteum
uterus
28
anterior pituitary
luteinizing hormone
chorionicgonadotropin
corpus luteum
placenta
uterus
29
anterior pituitary
luteinizing hormone
chorionicgonadotropin
corpus luteum
progesterone
placenta
progesterone
uterus
30
(No Transcript)
31
CONCENTRATIONS IN MATERNAL SERUM
non-pregnant
pregnant
32
Placental hormonesWhy shout?
33
Placental hormones originate as fetal attempts to
manipulate maternal physiology for fetal benefit
34
Placental hormones may evolve to become little
more than endocrine SPAM
35
maternal carbohydrate metabolism

• fasting blood glucose falls in first trimester
• maternal sensitivity to insulin decreases as
  pregnancy progresses
• maternal insulin production increases in parallel
  with reduced sensitivity

36
(No Transcript)
37
maternal blood pressure in pregnancy

• blood pressure reduced during most pregnancies
  rises toward term
• 10 women develop hypertension
• pregnancy-induced hypertension (PIH)
• preeclampsia (PIH proteinuria) affects 3
  pregnancies

38
Uteroplacentalresistance
Non-placentalresistance
Placental factors Maternal factors
decrease increase
increase decrease
39
(No Transcript)
40
Maternal-fetal relations lack important feedback
controls because signals are not evolutionarily
credible
41
non-pregnant mothers of sons

• time since birthof last son

• XY cellsin blood

6 months 10 months 12 months 2 yrs 3 yrs 6 yrs 7
yrs 27 yrs
no no yes yes yes yes yes yes
data from Bianchi et al. (1996)
42
(No Transcript)
43
(No Transcript)
44
data of E. B. Keverne
45
data of E. B. Keverne
46
Androgenetic/normal chimeras have large bodies
with relatively small brains
47
Gynogenetic/normal chimeras have small bodies
with relatively large brains
48
photos from E. B. Keverne
49
Contribution to brains of chimeric mice
hypothalamus
neocortex
two mums


two dads


Keverne et al. (1996)Developmental Brain
Research 92 91
50
Genomic imprinting concerns differences between
genomes of maternal and paternal origin, not
differences between males and females
51
(No Transcript)