Chickens changed to keep useful genes in eggs ^{CEFR B2}

Researchers at the University of Missouri report a potential method to produce a stable line of genetically modified chickens that lay eggs containing useful medical proteins. While eggs already serve to harvest proteins such as antibodies, making the trait heritable and stable has been difficult because inserted genes often become inactive over time.

The team addressed this problem of epigenetic silencing by using CRISPR to insert a new gene segment at a precise genomic site. They targeted the locus of GAPDH, an enzyme central to glucose metabolism that is active in every cell, and attached a green fluorescent reporter so they could monitor ongoing gene expression. Their hypothesis was that placing the segment in a constantly active location would prevent silencing.

After multiple months and many rounds of cell division the reporter genes remained brightly fluorescent, showing the introduced segment stayed active in those cells. This proof of concept opens the way to test whether the approach can form a production platform for stable bird lines. Lee and colleagues are collaborating with other scientists and industry partners to select useful modifications. Beyond medicine, the work may have agricultural and economic implications and could help if a gene is needed to reduce avian influenza transmission. The research appears in Poultry Science and was funded by the National Institute of Food and Agriculture.