The chromosomal 3D structure of mature sperm and eggs in mammals is revealed.

If human DNA is pulled in a straight line, it is about 2 meters long, but the diameter of the nucleus in general is only about 5 to 10 microns.
therefore, how genome DNA folds properly into the nucleosis is a very important scientific issue.
existing research shows that the three-dimensional spatial folding of genomic DNA plays a very important role in how the nucleus directs cell function.
for most animals, including humans, life begins with a combination of sperm and eggs.
however, the cell nuclei of sperm and the nuclei structure of eggs are very different from other sotic cells in our bodies.
Sperm cell nuclei are very small, only about 1/10 of the common nucleus, chromosomes are packaged by sperm protein, in a highly compressed state, while mature egg nuclei are in the middle of division, chromosomes are also in a highly compressed state, and most cells are still very different.
therefore, how chromosomes in the nucleus change and how they become normal cell chromosomes when sperm and eggs bind is a scientific question that has not been known.
, understanding changes in the advanced structure of chromosomes during mammalian development is helpful in understanding how humans develop from fertilized eggs into individuals.
Recently, the Liu Jiang Research Group of the Beijing Genomics Research Institute of the Chinese Academy of Sciences and the Huang Line Xu Research Group of Shanghai University of Science and Technology conducted a study on these issues, revealing the chromosomal 3D structure of mature sperm and eggs in mammals and the reprogramming of chromosomal structure during early embryonic development.
the limited number of mammalian matchers and early embryos, the team solved the challenge of using a small number of cells to create a 3D chromosome structure map to obtain high-resolution high-resolution chromosomal advanced structure maps of mouse sperm, eggs, and early embryos.
results show that mature eggs do not have topological domains (TADs), and ultra-remote chromosomal interactions are common in sperm.
studies have found that the advanced structure of chromosomes in fertilized eggs and 2-cell embryos is almost non-existent, and as development progresses, the advanced structure of chromosomes is gradually established.
study also found that the establishment of advanced structures of chromosomes does not depend on the activation of transcription of fertilized egg genomes, but on the replication of genomes.
addition, the study found for the first time a link between the advanced structure of chromosomes and DNA methylation, and found that early developmental DNA meddylation was also associated with the advanced structure of chromosomes.
This study provides an important basis for understanding how mammals develop from fertilized eggs into multi-functional individuals, and paves the way for scientists to understand the real 3D genome structure in early embryos, and the high-resolution high-resolution chromosomal high-resolution structural mapping data for early embryonic development in lactating cells will provide valuable resources for egediotic and bioinficies research and help uncover the mysteries of embryonic development."
results were published July 13 in the international journal Cell.
research was supported by the Chinese Academy of Sciences' Strategic Pilot Science and Technology Project, the National Natural Science Foundation of China and the Ministry of Science and Technology's National Key Research and Development Program.
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