Thursday, October 11, 2018
This Mouse Had Two Dads
lots of animals have reproductive strategies that seem almost alien to us. From penis fencing hermaphrodite flatworms to all female parthenogenic lizards. But why is it that mammals always seem to need a male and female? Scientists in China decided to see if other strategies can work, with a little help form science.
They were able to create mouse pups with two moms that even survived to adulthood. They did however have some abnormalities due to a process called imprinting, in which molecules with methyl groups attach at a location close to an affected gene in the DNA. These can be removed using CRISPR, and then the DNA of stem cells taken from the parents can be used to create embryos. Embryos created from females in this way have a 13% chance to produce viable offspring that are even able to reproduce at maturity.
These scientists even achieved something new, the first androgenesis ever in a mammal. It required some more work than using females. They had to cut out 6 imprinted regions to create embryos from the stem cells of two males, as opposed to 3 from the females. Only 1.2% of the embryos resulted in births (from a surrogate mom). None of those who were born lived for very long, and never to adulthood. They were also much larger than normal. The scientists learned that taking out a seventh imprinted gene made the offspring a normal size, though they still died.
This research might help us better understand birth defects caused by imprinted genes. It could also help with conservation of nearly extinct animals in which not enough individuals exist to revive the species through normal breeding, such as the northern white rhino which only has two female members left.