Ancestry.com Inc., the family history research website, is weighing a sale and working with Qatalyst Partners to find buyers, according to a person with knowledge of the situation. The Provo, Utah, company probably will attract interest from private equity firms, said the person, who declined to be identified because the process is private. Ancestry.com has a market capitalization of about $1.1 billion based on Wednesday’s closing share price. Social network providers, such as Google and Facebook, may see value in adding a family-centric service, said one analyst. Heather Erickson, a spokeswoman for Ancestry.com, declined to comment. A Qatalyst spokeswoman did not respond to a comment request.