Chinese scientists achieve breakthrough in human DNA assembly, cross-species transfer

TIANJIN -- A Chinese research team has made a significant leap in the field of synthetic biology by precisely synthesizing and assembling large-scale human DNA and successfully transferring it across species.

This achievement not only advances the technology of human genome synthesis but also opens new avenues for treating genetic disorders, according to the researchers.

The study, conducted by the state key laboratory of synthetic biology at Tianjin University, was recently published in the international journal Nature Methods under the title "De novo Assembly and Delivery of Synthetic Megabase-Scale Human DNA into Mouse Early Embryos."

The team, led by Yuan Yingjin, an academician with the Chinese Academy of Sciences, developed a method called SynNICE. This method involves assembling synthetic human genomic DNA in yeast and then extracting the yeast nuclei with intact chromosomes using a technique called NICE (Nucleus Isolation for Chromosomes Extraction). The extracted nuclei, carrying the synthetic DNA, were then injected into the early embryos of mice.

The researchers focused on a specific region of the human genome known as AZFa, located on the Y chromosome. This region is crucial for male fertility, and its deletion can lead to severe infertility with no current clinical solution. The AZFa region contains a high percentage of repetitive sequences, making it particularly challenging to synthesize and assemble. Despite this, the team successfully synthesized this region in yeast and transferred it to mouse embryos.

For the first time, the team observed the transcription of the synthetic human DNA in mouse embryos. This study not only shows how cellular environments can reshape synthetic genomes but also holds promise for future biomedical applications.