Nature's War Against Malaria

A study has found new evidence about the way human genome fights back malaria parasites. 

The international team was led by Sarah Tishkoff, a Penn Integrates Knowledge professor with appointments in the genetics department in Penn's Perelman School of Medicine and the biology department of biology in the School of Arts and Sciences, and Wen-Ya Ko, a postdoctoral fellow in the genetics department  at the medical school. 

University of Pennsylvania geneticists, in collaboration with an international team of scientists, performed a genetic analysis of 15 ethnic groups across Africa, looking for gene variants that could explain differing local susceptibility to malaria.

"When you try to identify the variants that are associated with disease susceptibilty, it's important to do a very fine scale study. Different populations evolve independently, to a certain degree, so different populations can come up with unique mutations," Ko said.
The life cycle of malaria depends on infecting red blood cells by binding to their surfaces, which is why mutations, such as sickle cell anaemia, that change the overall shape of those cells are thought to have experienced positive selection.
"Both host and the parasite try to fight back with mutations; it's a co-evolution arms-race that leaves a signature of selection on the genes," Ko explained.
"We've identified several single-nucleotide polymorphisms that are candidates for that signature," Ko said.
Across the 15 population sets, the researchers focused on polymorphisms in a pair of genes that code for proteins called glycophorin A and glycophorin B.