Scientists ditch sperm to create baby mice

Scientists in Shanghai have successfully combined genetic material from two female mice to create offspring without sperm, a breakthrough in the rules of reproduction that they say is unlikely to ever be applied to humans.

The team of scientists genetically modified an ovum-derived embryonic stem cell - the female sex gamete - and injected it into an ova to successfully produce a litter of baby mice. The research was published on Tuesday in Cell Research, a China-based international scientific journal.

"The entire process does not require any male involvement," Li Jinsong, the study's lead author, told the South China Morning Post.

"Sperm is replaceable - that's clear from the experiment. All we need are a pair of eggs, and from these eggs we can create a family, a colony, even a kingdom of healthy pups," Li said.

Zhong Cuiqing, one of the researchers in Li's team at the Institute of Biochemistry and Cell Biology, a branch of the Shanghai Institutes for Biological Sciences under the Chinese Academy of Sciences, said the success rate was surprisingly high.

"In our experiments, more than 15 out of 100 embryos finally developed into pups. They are healthy and show no difference in development and fertility from the ones that are naturally conceived," Zhong said.

Zhong said the success rate is surprising as the rate of regular artificial fertilization of that involves an egg and sperm-derived haploid cell in mice is between 20 percent and 30 percent. The team aims to elevate the ratio to 20 percent.

The scientists also conducted experiments on whether two sperm cells were able to create offspring, but these end in failure.

"For one thing, sperm is too small to make the procedure of artificial fertilization possible. For another, an egg is nutritious enough as the environment for a seed to sprout and grow while sperm is not," Zhong said. "An egg is a must as a receptor in external fertilization."

While the study makes major strides in reproduction research, it has raised concerns about any future use in humans. The scientists said that they will never apply the experiment to humans.

Li Yinhe, a sexologist and sociologist based in Beijing, also said the technique was unlikely to be applied to humans.

"It will trigger severe ethical problems if such techniques are applied to human beings as an assisted reproductive technology. The whole social order would be substantially changed," Li said.

"Any assisted reproductive technology in human society requires fairly lengthy and complex arguments in terms of social ethics before it is implemented clinically," Li said. "It must meet the social ethical standards."

Comments from a reviewer from Cell Research read, "This is an interesting and well conducted study that shows the deletion of two imprinted regions dramatically enhances mouse generation from androgenetic haploid ES cells via semi-cloning. In addition to the technical achievement this study is also of interest for researchers in genomic imprinting and epigenetic regulation."

zhouwenting@chinadaily.com.cn

(China Daily 11/21/2015 page2)