dr. ronald petersen and dr. richard hodes, thank you both very much. >> thank you very much. >> brown: online you can learn more about genetic testing and your own risk for alzheimer's, that's on our health page. >> woodruff: and now to kenya, a key u.s. ally. during last month's elections, only one part of the country saw violence: the coastal region, where 12 people were killed by separatist insurgents. and the coast also suffers from a religious divide-- it is a predominately muslim part of an otherwise christian nation. special correspondent kira kay recently traveled to the port city of mombasa to explore the new tensions. >> reporter: saturday mornings, the salvation army church in mombasa kenya is alive with choir practice. musical director charles muthama leads the rehearsal. >> we are very proud of this church, we are proud of the band, it is the only band in the coast, in the coast region. >> reporter: the salvation army is a christian congregation, nestled in the heart of a predominantly muslim city.