Researchers have edited the opossum genome, a task made more difficult due to the complicated reproductive biology of marsupials, MIT's Technology Review reports.
A Riken-led team used CRISPR/Cas9 to target the Tyrosinase (Tyr) gene in pronuclear-stage zygotes from the gray short-tailed opossum Monodelphis domestica. If one allele was successfully disrupted, the resulting opossum would be mosaic and if both alleles were disrupted, then it would be albino, Tech Review adds. As the researchers report in Current Biology, they generated five albinos, two mosaic, and eight wild-type coat color opossums with genome-edited alleles. Additionally, they crossed mosaic female opossums with male albino ones to confirm germline transmission.
As Tech Review notes, the researchers also had to contend with the difficulties posed by opossum reproduction and had to coax the animals to mate later in the day so that they could then inject the CRISPR machinery before a coating around the eggs became too hard.
"I think it's an incredible result," the University of Texas' Richard Behringer tells Tech Review, adding that "[t]hey've shown it can be done. Now it's time to do the biology."