Men vs Mice

The latest breakthrough in the field of mammal reproduction hints at a possible future in which men could be deemed obsolete.

At the Chinese Academy of Science, researchers have produced healthy mice pups with two mothers, no males involved.   This new work comes thanks to the amazing combination of stem cells and gene editing.

Unfortunately, when a similar process was attempted with two male mice, the offspring didn’t survive longer than two days.  Does this research endanger the relevance of the entire male sex!

The evil creature threatening the entire male sex. Image credit: Nick Harris (Flickr)


Why make mice from same-sex parents anyway?

Now it might seem a weird concept for animals to reproduce without both male and female sexes. However, when it comes to the wonderful diversity of the animal kingdom, there a variety of ways we create the next generation, not all of which require two sexes.

My personal favourite is parthenogenesis, in which the development of the embryo doesn’t require fertilisation. This means they can reproduce all on their own! It isn’t seen often, but has been observed in several species including; lizards, snakes, fish and even birds. Some species have all the options, and can even reproduce by both sexual reproduction and parthenogenesis, such as the ancient Komodo dragon.

The Komodo dragon, capable of reproducing by both sexual reproduction and parthenogenesis. Image credit: Poppet Maulding (Flickr)

However, alternative reproductive methods such as parthenogenesis, are not seen at all in mammal species. This new research aimed to gain insight into what is restricting us to the two-sex approach. So, what was the best way to analyse mammal reproduction? See if we can break it.


So, how did they break mammal reproduction?

We have genes which are required for our development into an embryo. Some of these are shut down by ‘imprinting’ genes. Mammals normally require both a mother and a father to stop these ‘imprinting’ genes from interfering. However, if the ‘imprinting’ genes are removed from our DNA then the problem is avoided. Simply put, that’s exactly what the researchers did. Using the forefront of gene editing technology, CRISPR, the researchers deleted the ‘imprinting’ genes.

The team took edited stem cells, specifically haploid stem cells, from one mother, then injected them into an egg cell from another mother. Both the egg and stem cell contain half of the information required for a complete mouse, which made this process possible. Haploid stem cells were used because they naturally contain lower amounts of the problematic ‘imprinting’ genes making the overall process more successful.

The breaking of mammal reproduction was successful. From 210 embryos, 29 produced live mice, each capable of reproducing on their own. For a new practice such as this, 29 is a significant result.

When the researchers used a similar approach with male mice they were not met with such success. No mice pups survived 48 hours after birth.


What about us?

This ground-breaking technique has the potential to be used on other mammals, us included. So, one could imagine that one day the male sex would no longer be required for the human race to continue.

My face after realising I might no longer be needed (not actually my face). Image credit: Si Wilson (Flickr)


There are also questions to be answered about the morality and method behind editing our own DNA.  We would also seek reassurance that children would have every opportunity of survival and health and wellbeing would not be compromised.

However, assuming all those barriers are passed, there is hope for everyone! The team is aiming to change and improve the process so that the two-male approach could one day also be possible. This would mean couples of all forms could have biological children of their own. At the end of the day men are not going to be obsolete, and everyone wins – a happy ending!


One Response to “Men vs Mice”

  1. Daniel Hutchinson says:

    Great post Josh
    You took a really complex scientific study and I think you’ve made it something that’s fun and easy to understand for everyone