The authors of the latest study indicate that there probably is underreporting in the study because of population movement, inherent errors posed by dealing with samples, and inability to visit some households because of security problems.

CNN: Study: 151,000 Iraqis slain as of June 2006

Today Stefansson has collected DNA samples and records from some 70, 000 volunteers, a quarter of the population.

FORBES: Icelandic identifiers

Today Stefansson has collected DNA samples and records from some 70, 000 volunteers, one-quarter of the population.

FORBES: The E-Gang: Medical Marvels