The process comes full circle when conditions change again, turning the gene back on.

BBC: Body clock 'set before birth'

The feeling that, if this group of 100 is the inner circle, imagine the kind of change this Power Matrix can affect.

FORBES: Michelle Obama, Anna Wintour & Oprah��s Inner Circle of Power

Reshma Shetty thinks an empty-looking circle on a plain piece of paper could change the world.

FORBES: Do-It-Yourself Life

Mr Castles and Mr Henderson argue that the circle of those involved in the climate-change exercise has been too restricted.

ECONOMIST: Economics focus

Lead character Carrie Bradshaw and her circle of friends are credited with having helped change attitudes among young people towards sex.

CNN: The day in numbers: 2,000

Mr Cameron said Mr Barker, a Conservative MP who visited the Arctic Circle with him in 2006 to investigate climate change, was "doing an excellent job".

BBC: David Cameron and Greg Barker

This change proved more than his elite social and financial circle could accept, and they ostracized him for it.

FORBES: The Alchemist

The EU and US imposed sanctions on Mr Mugabe and his inner circle after accusing them of unleashing violence and rigging previous election to prevent Mr Tsvangirai and his Movement for Democratic Change (MDC) from taking power.

BBC: Zimbabwe 'bars' EU and US from observing polls