The brains of two genetically engineered girls born in China may have been changed in ways that enhance cognition and memory.

New research shows that the same alteration introduced into the girls’ DNA makes mice smarter and improves human brain recovery following a stroke. The findings suggest that the controversial gene editing experiment to make the girls resistant to HIV likely enhanced their ability to learn and form memories.

The twins, called Lulu and Nana, had their genes edited before birth by a scientific team led by doctor He Jiankui using the gene editing tool CRISPR. The goal was to make the girls immune to HIV infection. To achieve this they deleted the CCR5 gene, which is required for HIV to enter human blood cells. According to a new report, in the journal Cell, people who naturally lack CCR5 recover more quickly from strokes and people missing at least one copy of the gene seem to go further in school.

Other research has shown that removing the gene from mice significantly improved their memory. Scientists think CCR5 acts as a suppressor of memories and synaptic connections.

Image: “oxygen pathways in the brain” by Viktor Brezinsky is licensed under CC BY-SA 2.0