Unrest in the Middle East sent gold futures prices sharply higher Friday as investors sought safe havens, and exchange-traded funds that track the metal followed suit. Gold was recently trading up $13.10 to $667.50 an ounce. Shares of iShares Comex Gold Trust ( IAU) ETF was higher by 85 cents, or 1.3%, to $66.45. The streetTracks Gold Shares ( GLD) ETF was up 80 cents, or 1.2% to $66.35. The Homebuilders SPDR ( XHB) ETF slid nearly 4% after D.R. Horton ( DHI) posted a drop in third-quarter new-home orders and cut its full-year earnings guidance. The homebuilder ETF recently was trading down $1.16 to $30.01. The PowerShares Dynamic Building & Construction Index ( PKB) ETF, meanwhile, was down 39 cents, or almost 3%, to $14.19. The iShares Dow Jones U.S. Home Construction ( ITB) ETF was down $1.45, or 4%, at $34.38. The Biotech HOLDRs Trust ( BBH) was down nearly 3% after two of its biggest components, Genzyme ( GENZ) and Genentech ( DNA), headed lower on Friday. Genentech was recently trading down $2.18, or 3%, to $78.57. Genzyme was recently trading down 76 cents, or 1.2%, to $62.18. The biotech ETF was trading down $4.50 to $170.77. The PowerShares Dynamic Biotech & Genome ( PBE) ETF was lower by 33 cents, or 2%, to $15.34. Shares of the iShares Russell 2000 Index ( IWM) traded actively after several of its component stocks moved lower Friday. Shares of top holding Amylin Pharmaceuticals ( AMLN) were down $1.59, or 3%, to $48.01. Shares of the Russell 2000 ETF were trading down 56 cents to $67.51.