Parent-Offspring Conflict Flashcards
Is pregnancy normal?
Not really as most creatures have their young outside and there is a huge cost to having young within you
What is natural selection?
Genes transfer into the next generation - if a gene improves the fitness of the individual it is more likely to survive to the next generation. Genes which are ‘fitter’ will be inherited more readily than others.
What is inclusive fitness?
You can pass fitness and genes by looking after those around you (altruism) as people you are genetically related to can pass on their genes (which are similar to yours)
How related are you to your grandparents, parents, siblings and half siblings?
Parents - 50%
Grandparents - 25%
Half siblings - 25%
Siblings - 50%
When should you be altruistic? (Hamiltons Rule)
rb>c
r - relatedness coefficient
b - benefit of recipient
c - cost to actor
When to be selfish?
rb<c
Sun fish release 300 eggs to their own devices and deliver no care - what type of things would cost the sunfish too much if they were to look after young?
They could be eaten by seals
What is relatedness asymmetry and what behaviours can this cause?
You want all resources to yourself whereas your parents want to split it equally between their children.
This causes behaviour such as sibling rivalry, intrauterine cannibalism, chicks begging for food even if they have had enough.
What are the interaction interphase between mother and fetus and why is this part of the arms race?
This occurs in the placenta - transfer of nutrients and waste and lack of maternal barrier could cause the baby to take more nutrients than it needs and the mother wants to give - arms race
What is some evidence of the arms race?
Protease activity causes invasiveness and the mother inhibits this. If there is no inhibitors you get an ectopic pregnancy. Could also cause pre-eclampsia
What is involved in the endocrine arms race?
Fetal hormones (human placental lactogen) bind to prolactin receptor causing insulin resistance so the fetus gets more glucose
What are some alternative hypothesis to the arms race?
Mutual advantage hypothesis
How could increased invasiveness and increased maternal blood sugar be part of the mutual advantage hypothesis?
Increased invasiveness could cause ectopic pregnancy but helps reduce preclampsia and increased offspring size
Increased maternal blood sugar could get a healthier baby and wont kill the mum
What are types of conflicts that could occur?
Parent - parents conflict
What things are involved in parent-parents conflict?
There is an asymmetrical reproductive costs which can influence genetics
What is DNA methylation?
This binds to the DNA causing the DNA to tighten and the genes not to be transcribed.
what is maternal genomic imprinting?
Some of the maternal genes are methylated and turned off but the fathers wont be
Why are some maternal genes turned off and not paternal?
These must benefit the mother in some way - these genes control fetal growth (if they have a gene for big babies they turn it off to help with delivery), metabolism (also helps with having average sized babies), placenta development (invasiveness) and suckling.
Why would the male want a big baby and a female not?
Better for competition and passing on their own genes.
More risk of difficult delivery and death
What ways could genetic imprinting go wrong?
- mutations or damage
- paternal genome imprinting
- offspring does not express the gene on either chromosome
Angleman Syndrome
Paternal imprinting causes UBE3A gene to be turned off
Causes small head, intellectual impairment, seizures, co-ordination challenge
Beckwith-Wiedemann syndrome
CDKN1C gene turned off by paternal imprinting causing overgrowth, cancer risk, large head and one leg longer than the other.
