Chinese scientists successfully create the world’s first mammal with completely reprogrammed genes

Chinese scientists have successfully recombined mouse chromosomes to create the world’s first mammal with completely reprogrammed genes.

Using the CRISPR gene-editing tool, researchers at the Chinese Academy of Sciences (CAS) in Beijing he broke down the chromosomes into different segments and rearranged them in different combinations to create a new package of genes, resulting in the mouse called “Xiao Zhu” (little bamboo).

The article, published in the academic journal Sciences on Thursday, revealed that the research team achieved the first gene modification in mammals on a scale as large as chromosomes.

Chromosomes, which contain the DNA in the nuclei of cells, naturally separate and recombine through a complicated and delicate process. In the past, humans have only managed to replicate the process in a laboratory with single-celled organisms such as yeast.

“Mammalian genomes are much more complex than yeast genomes, and complete chromosome rearrangements in mammals have not been successful,” said Li Wei, lead author of the study and a researcher at the Institute of Zoology of the Academy of Sciences. from China. quoted saying.

Errors during such chromosome separation and fusion under natural conditions occasionally result in cancer and other serious conditions.

When Li and his colleagues manipulated the chromosomes by joining two very long pieces of a chromosome, they also made some mistakes that resulted in the death of the mice produced or in specimens with deformities or strange behavior.

Using shorter chromosomes and reducing the total number of chromosomes from 20 pairs to 19 allowed them to create a new karyotype in mice that appeared healthy and normal despite having completely different chromosomes than mice in the wild.

“For the first time in the world, we have achieved a complete chromosomal rearrangement in mammals, which represents a new breakthrough in synthetic biology,” Li said. “This research is a breakthrough in bioengineering technology, helping to understand the impact of large-scale remodeling on mammalian chromosomes and to gain a deeper understanding of the molecular mechanisms behind growth and development, evolution reproductive and even the creation of a species.”

The reprogrammed mice were able to mate and have offspring with normal mice, suggesting that the artificial changes may be passed down from generation to generation.

The mice, however, bred at a much lower rate than standard lab mice due to an abnormality in the way the chromosomes separated after alignment.

According to scientists, its breakthrough could potentially lead to cures for conditions such as infertility and diseases such as cancer, as it allows researchers to observe and control chromosomes in mammalian cells.

In 2018, Associate Professor of South China University of Science and Technology (SUSTC) He Jiankui attracted almost universal criticism for creating the world’s first gene-edited babies using CRISPR. He was released from prison in April this year after being sentenced in January 2020 for deliberately violating China’s biomedical regulations.

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