Google has expanded its mission to lay bare the world’s information by investing in a company set up by its co-founder’s wife that lets users trawl their genetic profile online.

The move comes as Google, keen to present itself as a benign Big Brother, radically extends its efforts to build precise profiles of online consumers to target advertising campaigns more precisely.

It emerged yesterday that Google has invested $3.9 million (£1.9 million) in 23andMe, the biotech company co-founded last year by Anne Wojcicki, a former health sector analyst who recently married Sergey Brin, the search giant’s billionaire co-founder.

By encouraging individuals to learn about their own genetic information, 23andMe aims to create an “open resource” that can help to accelerate drug discovery and bring about a revolution in personalised medicine.

Mr Brin, worth an estimated $14 billion, also personally provided about $2.6 million in interim debt financing to Ms Wojcicki’s start-up.

According to Silicon Valley folklore, the couple met after Ms Wojcicki’s sister rented her garage to Mr Brin and his partner, Larry Page, to serve as Google’s early offices.

“Even though your body contains trillions of copies of your genome, you’ve likely never read any of it,” 23andMe states on its website. “Our goal is to connect you to the 23 paired volumes of your own genetic blueprint (plus your mitochondrial DNA).”

It will also echo the style of social-networking sites. “By connecting you to others, we can also help put your genome into the larger context of human commonality and diversity,” the company said.

Google said that the investment was made as 23andMe’s “goal of developing new ways to help people make sense of their genetic information will help us further our mission of organising the world’s information in this new and important field.”

Eric Schmidt, the search giant’s chief executive, said this week that Google was still at a “very early” stage in terms of collecting personal data through the web. The company does not yet “know enough about you”, he said.

The main thrust of Google’s mission to collect data is being made through its “personalised search” programme – a service it stresses is ring-fenced from its other activities such as the 23andMe investment.

Google users already have the option to access and edit their search histories. The “ultimate dream” is to harness this information to give users advice on topics as diverse as their career paths and what they should do on days off.

Google has stressed that users have the option to opt out of the service and says that it will not use information unless it receives a “valid legal order”.

Other 23andMe investors include Genentech, the biotech company, whose chief executive, Arthur D. Levinson, is a Google director, as well as New Enterprise Associates and MDV-Mohr Davidow Ventures, the venture capital firms.