Investigators in the laboratory of Stephen Warren, PhD, chairman
of human genetics at Emory University School of Medicine, used
DNA microarray technology to read variant sites across the
entire genomes of 471 Ashkenazi Jews. The work comes from a
collaboration between Warren and Ann Pulver, ScD, associate
professor of psychiatry and behavioral sciences at Johns Hopkins
University School of Medicine, who recruited the participants
for a study of schizophrenia genetics. Researchers looked for
close to one million single nucleotide polymorphisms (SNPs):
common alternative spellings in the genome, analogous to
American and British spellings of words such as
organize/organise. One measure of genetic diversity in a
population is heterozygosity, or how many of the SNPs inherited
from the mother and father are different; a more inbred
population has less heterozygosity. "We were surprised to find
evidence that Ashkenazi Jews have higher heterozygosity than
Europeans, contradicting the widely-held presumption that the