|same-sex mice gave birth thrugh genetic engineering method/ Photo By Kampol Taepanich via Shutterstock|
Scientists in China have birthed healthy baby mic using a new genetic engineering method, using the DNA of two same-sex parents. The baby mice are born without defects and it developed normally and went on to produce healthy offspring. The Forbes posted on their online portal that researchers at the Chinese Academy of Beijing have successfully deleted specific segments of DNA in order to genetically engineer a healthy mouse embryo from same-sex parents. Unfortunately, the baby mice which had two fathers only survived for 48 hours but the researchers still consider it as a remarkable event for the genetic engineering.
The scientist from China conducted the study in order to know why mammals require to have intercourse to have offsprings, explained by BBC on their website. Humans and other mammals reproduce by means of having intercourse with another gender since reproduction needs an egg and a sperm from each of the parents. However, scientists are puzzled as to how other species like plants, fishes, reptiles, and amphibians reproduce since they could do sexual reproduction alone. “We were interested in the question of why mammals can only undergo sexual reproduction,” says Qi Zhou, one of the researchers at the Chinese Academy of Sciences. He also added that they are trying to find out if there is a possibility of producing normal mice while having same-sex parents which could be done using haploid embryonic stem cells with gene deletions.
Meanwhile, Science Mag also reported that way back in 2004, a different team also conducted the same technique using two mouse moms, but just like the current experiment, one of the 10 mice was born and successfully grown to adulthood and scientists claim that the technology used is still dangerous and too risky for humans to use. “However, the generated mice still showed defective features, and the method itself is very impractical and hard to use,” said Zhou.
How did they do it?
The scientists involved in the experiment describe the complex process of using embryonic stem cells and gene editing to produce mice born from two parents of the same sex. The mice with two dads only lived about 48 hours, but the mice with two moms lived to adulthood and were able to have babies of their own by mating with male mice. The research provides a new, sophisticated result that’s part of a significant body of research exploring the question of why people need two parents of different sexes at all. In achieving the successful births, the researchers proved that they had identified and overcome the factor that makes joint male-female involvement in reproduction essential for humans. Critics also said that the study could create a new way for single-sex humans to reproduce in the future.
|imprinting is one reason why genetic information from two female or male mice can’t be combined to produce a viable offspring/Photo By Nixx Photography via Shutterstock|
BBC also explained that the researchers who used two female mice took an egg from one female mouse and added a special type of cell called, haploid embryonic stem cell which they obtained from the other female mouse. The researchers also had to use gene editing in order for them to delete three sets of genetic instructions which would make the genetic instructions to be compatible with each other. Meanwhile, scientists from the Chinese Academy of Sciences took out a sample of sperm, a male haploid embryonic stem cell, and they also obtained an egg which had all of its own genetic information removed and the deletion of seven genes to make it all work.
The scientists also focused on a phenomenon known as “imprinting”, where for roughly 100 genes, only the copy that comes from the mother or only the copy that comes from the father ever becomes “switched on”. In human embryos, the male genes make up for the females ones that are not switched on and vice versa. To overcome the barrier of having missing same-sex genes, the scientists obtained some embryonic stem cells from a female mouse and used the gene-editing CRISPR-Cas9, which has been linked to a genetic pair of scissors and were able to remove maternal imprinting by cutting out a single letter of genetic code from three crucial regions.
Imprinting is one reason why genetic information from two female or male mice can’t be combined to produce a viable offspring without genetic alterations. Male and female mammals each carry the same number of chromosomes, a matched set that needs to zip together in order for the DNA to successfully code for the proteins that make life possible. This means that one half of the genetic information needed should be from a female and the other half is from a male.
What is CRISPR- Cas9?
Live Science defined CRISPR-Cas9 as the specialized stretches of DNA where the protein Cas9 acts like a pair of molecular scissors which are capable of cutting strands of DNA. CRISPR technology was adapted from the natural defense mechanisms of bacteria and archaea and these organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. These enzymes do so primarily by chopping up and destroying the DNA of a foreign invader.