PM, it starts from appointing them as head of a particular party when they are young (For eg. coming back to Nehru family - Rahul Gandhi). They are groomed by the senior members and thereafter when the time is favourable they are introduced in the system. That is how it goes in the sub continent. Since this way of thinking is so typical, Mahatma Gandhi had a tough time changing laws to accomodate 'harijans' or the low caste hindus on higher posts because they were always supposed to do the 'cleaning toilets' job. Infact they had brooms attached to their pants so that it sweeps the earth after they walk.