In this week's Science, a team led by Stanford University researchers reports on a new technique for identifying recent changes in allele frequencies using contemporary genome sequences, which they used to study selected-for traits among the ancestors of modern Britons during the past 2,000 years to 3,000 years. Called the Singleton Density Score, the method was applied to evaluate selection signals in more than 3,000 modern genomes from selected from the British population. The researchers were able to measure recent changes in allele frequencies, revealing that polygenic adaptation affected traits such as increases in height, infant size, birth weight, and female hip size. They add that their method can be applied to other populations and species.
And in Science Translational Medicine, a multi-institute group of investigators reports on the use of CRISPR/Cas9 genome editing to correct the genetic mutation that causes sickle cell disease in patient blood stem cells, which they were able to engraft into mice for up to four months. The corrected stem cells produced less sickle hemoglobin RNA and protein and correspondingly increased wild-type hemoglobin when differentiated into erythroblasts, the study's authors report. When the cells were engrafted into immunocompromised mice, they maintained their sickle cell disease gene edits for 16 weeks at a level believed to have clinical benefit. The findings open the door for a new approach to treating a condition that affects an estimated 90,000 predominantly African-American individuals in the US and hundreds of thousands worldwide. The Scan has more on this study here.