When reproducing some reptiles, amphibians, and fish can procreate with same-sex parents, however, it’s challenging for mammals to do the same even with the help of fertilization technology.  Now, a study from researchers at the Chinese Academy of Sciences produces healthy mice with two mothers that consequently had normal offspring of their own.  The team states their study explores what makes it so challenging for animals of the same sex to produce offspring and suggests some of these barriers can be overcome through the use of stem cells and targeted gene editing.  The opensource study is published in the journal Cell Stem Cell.

Previous studies show certain maternal or paternal genes in mammals are shut off during germline development by a mechanism called genomic imprinting, meaning offspring might experience developmental abnormalities or be unviable when they don’t receive genetic material from both an adult male and female. By deleting imprinted genes from immature eggs, researchers have produced mice with two mothers, however, the generated mice showed defective features.  The current study investigates whether normal mice with two female parents or even mice with two male parents could be produced using haploid embryonic stem cells with gene deletions.

The current study utilizes haploid embryonic stem cells containing half the normal number of chromosomes and DNA from only one parent to create mice with two mothers.  This was accomplished by deleting three imprinting regions of the genome from the haploid embryonic stem cells containing a female parent’s DNA and injecting them into eggs from another female mouse.  Results show twenty-nine live mice were produced from 210 embryos.  Data findings show the mice were normal, lived to adulthood, and had offspring of their own.

The lab states they also produced twelve live, full-term mice with two genetic fathers with a similar procedure, however, these pups only survived 48 hours after birth.  They go on to add their data reveals some of the most important imprinted regions hindering the development of mice with same-sex parents, also interesting for studying genomic imprinting and animal cloning.

The team surmises their study shows the defects in bi-maternal mice can be eliminated, with bi-paternal reproduction barriers in mammals also crossed through the use of imprinting modification.  For the future, the researchers state they plan to explore these techniques in other research animals.

Source: Chinese Academy of Sciences