We are studying DNA in order to look at the way genes (nature) and lifestyle (nurture) are related to feelings, behaviour, health, and development. It will help us to understand how nature and nurture work together. Although we all have very similar genes, there are many small variations. These different versions of our genes can make us more or less likely to develop many common diseases, such as allergies (asthma, for example), diabetes or heart disease. These differences can also affect our personality and behaviour.