Contents

30 July 1993
Vol 261, Issue 5121

About The Cover

Adult female Anopheles gambiae mosquitoes, the principal malaria vector in Africa. A sex-linked recessive mutation that changes the wild-type (right) eye color to white (left) has been mapped genetically on the X chromosome. See page 605 and the News story on page 546. [Photo: Jim Gathany, Centers for Disease Control Photoservices]