Weaver et al 2004

Question 1

my study for

Answer 1

epigenetic changes in rats

Question 2

aim

Answer 2

measuring the effect of maternal behaviour in rats on epigenetic changes in their offspring

Question 3

subjects

Answer 3

rats raised in captivity, majority of which came from laboratory environments

Question 4

procedure

Answer 4

1. the rat mothers’ maternal nurturing were asessed by reaserchers
2. the pups were divided into conditions, with mothers who scored low, who had little to none nurturing LOW LG-ABN
   or the HIGH LG-ABN conditions, where mothers were highly caring and nurtuting
3. DNA methylation was measured by the researchers when the pups were one week old and this continued during the course of the rats’ lives
4. The pups who had been raised by a high LG-ABN mother were then given to a low LG-ABN mother - and vice-versa - so that each pup experienced the opposite type of maternal care from their rat ‘foster mother’

Question 5

results

Answer 5

The pups who had experienced high levels of LG-ABN showed more differences in their DNA methylation than the pups who had experienced low LG-ABN i.e.

the pups who had originally been raised by a nurturing biological mother showed more epigenetic changes than the pups who had been raised by an unloving mother

the DNA methylation changes were observed to be long-lasting, going from the first week of the pups’ lives well into adulthood

Question 6

conclusion

Answer 6

Epigenetics can change the state of specific genes and this can occur through learnt experiences either early or later in life. These changes are also reversible.

Question 7

strength

Answer 7

the use of a standardised procedure in lab conditions mean that the findings of this study could be tested via multiple replications

REPLICABLE – GIVES IT VALIDITY

Question 8

LIMITATIONS

Answer 8

The results of this study cannot explain exactly why the epigenetic changes occurred: they could have been due to an array of variables which had nothing to do with LG-ABN: this decreases the internal validity of the study

LACKS ECO VAL The sample of rats used was taken from a laboratory facility so the experience of nurture and stress is likely to be different to animals in the wild who will have far more threats and danger to contend with i.e. it lacks ecological validity