Human evolution: The strongest links

One approach to mapping disease genes and tracing population history involves resolving the human chromosomes into underlying 'ancestral segments' - regions that have been passed down through the generations largely intact from the founders of a population. Evidence for the ancestral segments is measured as 'linkage disequilibrium' among variants along the chromosome, and this parameter is also used to detect the presence of variants near or in disease genes. The first large-scale investigation of linkage disequilibrium is reported this week. Linkage of 19 genomic regions was determined in populations of European Americans and Africans. The results are revealing both in terms of disease mapping and population history. The data point to a demographic bottleneck in northern Europe between 30,000 and 50,000 years ago, perhaps a relic of depopulation in the ice age, or a recent 'out of Africa' scenario.

Linkage disequilibrium in the human genome
DAVID E. REICH, MICHELE CARGILL, STACEY BOLK, JAMES IRELAND, PARDIS C. SABETI, DANIEL J. RICHTER, THOMAS LAVERY, ROSE KOUYOUMJIAN, SHELLI F. FARHADIAN, RYK WARD & ERIC S. LANDER
Nature 411, 199-204 (10 May 2001)
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lifelines: a long stretch in the cell

10 May 2001 table of contents