Haploid cells and the individuals they develop into are ideal models for studying recessive inheritance. Mammalian haploid cells in natural state are limited to cells with specialized structures and functions, such as eggs and sperm. However, eggs and sperm cannot be cultured in vitro, and genetic manipulations are difficult. If a mammalian haploid cell line can be established in vitro, it will greatly promote the research on mammalian gene function and genetics.

In view of the characteristics that haploid parthenogenetic embryonic stem cells can replace sperm, gene modification through genetic manipulation of haploid stem cells can directly pass on to offspring, avoiding harsh requirements of other transgenic methods in germline chimerism. This may greatly improve the efficiency of gene modification and its application range. 

The collaborative team of LI Jinsong and XU Guoliang from Shanghai Institute of Biochemistry and Cell Biology of the Chinese Academy of Sciences (CAS), and another collaborative team of ZHOU Qi and ZHAO Xiaoyang from the Institute of Zoology of CAS, established mouse haploid stem cell lines using nucleus transfer and stem cell technology, respectively.

These haploid stem cells have typical mouse embryonic stem cell characteristics and developmental potential, and can form chimeric mice; when these cells are injected into oocytes, they can replace sperm to complete fertilization and produce healthy mice; genetical modification on these cells will generate healthy and fertile transgenic and gene knockout mice quickly and easily, which greatly shortens the process of gene modification and improves its efficiency.

Related results were published on Cell and Nature respectively.

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