A gene-edited mouse created with two male parents has now survived to reach adulthood. This is a momentous occasion for genetics, as previous attempts to create bi-paternal mice have failed for a variety of reasons. Now, though, scientists have at least one success story to build off.
This breakthrough is the result of years of research into overcoming the genetic barriers that prevent unisexual reproduction in mammals. Using advanced stem cell engineering techniques, researchers from the Chinese Academy of Sciences and Sun Yat-sen University targeted 20 key imprinting genes.
These are the genes that regulate how genetic material is expressed during development. Modifying these genes through gene deletions and frameshift mutations could correct developmental defects that had previously prevented bi-paternal embryos from surviving. This allowed the gene-edited mouse to survive in childhood.
The success of this research is significant not only for reproductive science but also for stem cell biology. The gene modifications not only allowed some bi-paternal mice to reach adulthood but also improved the stability of pluripotent stem cells.
This means that beyond reproductive applications, the findings could have implications for regenerative medicine, potentially improving techniques used in cloning and therapeutic stem cell treatments. Being able to heal terrible wounds by regenerating cells has long been a goal for medical researchers.
However, major challenges remain. Despite this milestone, only 11.8 percent of viable embryos developed into live mice, and many of those that did were born with developmental defects. Even those that reached adulthood had altered growth patterns, shorter lifespans, and were completely sterile.
The scientists believe further refinements to imprinting gene modifications may eventually lead to healthier bi-paternal mice capable of producing viable offspring. With this gene-edited mouse reaching full adulthood, though, the scientists are now moving focus to larger animals, such as monkeys.
This could bring it one step closer to potential medical applications. However, the genetic differences between mice and primates mean that such research will require considerable time and effort before it’s ready to be displayed.
There are also ethical concerns surrounding this type of research. The International Society for Stem Cell Research currently prohibits heritable genome editing for human reproduction, and using human stem cell-derived gametes to create viable embryos is considered unsafe.
While the goal of this research is not human reproduction, it does raise new questions about the future of genetic engineering and its potential applications and how scientists might push past the current boundaries that have been established, especially since we’ve seen scientists genetically edit babies in the past.