PAR, Thrifty Phenotype

Question 1

Against PAR: finnish mums with bad start AND bad breeding environment do particularly badly… Under PAR you’d expect them to do fine, as they should be prepared for a poor environment

Answer 1

Robinson et al. in prep

Question 2

Effect of pre-natal runting on post-natal development of skeletal muscles in pigs & rats

Answer 2

Hogarty & Allen 1978

Question 3

In meadow voles, offpsring born in summer have thin adult coat, those born in winter have thick adult coat!

Answer 3

Lee & Zucker 1988

Question 4

Seige of Leningrad an example of successful PAR, as post-natal nutrition did not improve (compared to dutch/WWII examples)

Answer 4

Bateson 2001

Question 5

PAR in humans, overview, problems and hypothetical testing.
Examples of possible ‘sruvival phenotypes’ as a result of poor early conditions, e.g. insulin resistance (reduces energy invested in growth and metabolism), reduced skeletal mass (decreases energy demands of maintaining adult body).

PAR may be more feasible in shorter-lived animals where it is more likely that the developmental environment will be the same as that during reproduction in adulthood.

Alternatives to PAR: thrifty phenotype (immideiate survival), or that PAR is only focused on getting individual through immediate post-natal conditions.

Infant prediciton would make more sense (60-75% of chilcred make it to adulthood in pre-medical society), and reliability of environmental prediction declines with time.

Also, reduced size as a supposed affect of PAR might make you less attractive to mates, which would go against the idea that you would prioritise reproductive fitness over longevity… though maybe that is the best you can do.

Background costs of maintaining plasticity necessary for PAR also need to be taken into account, must outweigh coast of not having a PAR phenotype

Answer 5

Rickard & Lummaa 2007

Question 6

Proposed that fat deposits in early childhood are a short-term survival tactic, and that high insulin-resistance is in fact just a result of this rather than a lifelong PAR survival phenotype

Answer 6

Kuzawa 1998

Mittleman 2002

Question 7

The PAR hypothesis proposes that the fetus responds to maternal undernutrition or stress by inducing the ‘survival phenotype’, which it predicts will benefit it in its
postnatal life.

Answer 7

Rickard and Lummaa 2007