"Whites can't jump".
Asians are good at martial arts... And so on.
But stereotype images also apply to the conditions that affect each race.
And this time is for real. Tay-Sachs disease favors Ashkenazim Jews (of European descent), while cystic fibrosis haunts White people. Latin Americans and African rooted people are particularly vulnerable to type 2 diabetes, 90% and 60 % more than White people. Hypertension plagues Afro-Caribbean descent at a higher rate than other populations.
International HapMap Project is a global effort to assess single-nucleotide variations, to understand the connection between race and common complex genetic diseases. "But the efforts
have borne little fruit," said Vivian Cheung, a human geneticist at the University of Pennsylvania School of Medicine.
That's why Cheung and geneticist Richard Spielman used microarray technology to analyze the expression of many genes at once, across Mongoloid and White populations for many different traits displayed by a type of white blood cell. The team found that different races not only carried different genes, but there were big differences in the gene expression.
Rather, different trait qualities were not determined by variation inside the gene composition, but by variation in noncoding adjacent regions of the genes, that regulate the gene activity.
The new study also points that large-scale changes to DNA are also involved in differences between ethnic groups. The team checked 4,197 genes and when they compared the Mongoloid populations with the White ones, they discovered that 1,097 (more than a quarter) of the genes were differently expressed. The expression level disparities were mostly due to genetic differences in noncoding regions around the genes, and not in the genes themselves. "We were able to pinpoint 11 genes where people have different forms of the regulator," Cheung reveals.
"Let's say that among the Caucasian population, maybe the regulator that turns on the gene more happens to be more frequent--overall the expression level of that gene will be higher. Whereas in the Asian population, more people have the regulator that causes the expression level to be lower."
"One of the things that's exciting about this work is that identifying the genetic variants that account for gene expression differences could help the field to find those genetic variants that affect disease risk," said Steve McCarroll, a population and medical geneticist at the Massachusetts Institute of Technology's Broad Institute.