Kevin Clarke, whose portrait of James Watson is this month’s Blunt End, lives in New York City and is developing a book and exhibitions exploring the role of genetics in the aftermath of the 9/11 attack on the World Trade Center. Clarke’s work is currently on view in “How Human? Life in the Post-Genome Era” at the International Center of Photography, New York, through June 8, and in “Four Plus: Writing DNA” at the Wellcome Trust, London, until July.