Mr. Brady shared the details of the cloning on Tuesday in a news release issued by Colossal Biosciences announcing that it had acquired Viagen, a biotechnology company. Viagen owns the rights to the technology that was used to clone Dolly the sheep in 1996. Mr. Brady, who is an investor in Colossal, said that he had worked with the company a “few years ago” and that the cloning process required a “simple blood draw” from the family’s elderly pit bull mix, Lua, before she died.