Researchers engineer first sustainable chromosome changes in mice sciencemagazine
, the researchers reveal that chromosome-level engineering can be achieved in mammals, and they successfully derived a laboratory house mouse with novel and sustainable karyotype, providing critical insight into how"The laboratory house mouse has maintained a standard 40-chromosome karyotype—or the full picture of an organism's chromosomes—after more than 100 years of artificial breeding," said co-first author Li Zhikun, researcher in the Chinese Academy of Sciences Institute of...
Such small changes may have big impacts, according to Li. In primates, the 1.6 changes are the difference between humans and gorillas. Gorillas have two separate chromosomes whereas in humans they are fused, and a translocation between ancestor human chromosomes produced two different chromosomes in gorillas. At an individual level, fusions or translocations can lead to missing or extra chromosomes or even to such diseases as childhood leukemia.
While the consistent reliability of the chromosomes is good for understanding how things works on a short-time scale, the ability to engineer changes could inform genetic understanding across millennia, including how to correct misaligned or malformed chromosomes, Li said. Other researchers have successfully engineered chromosomes in yeast but attempts to move the techniques to mammals have not been fulfilled.
According to co-first author Wang Libin, researcher with CAS and the Beijing Institute for Stem Cell and Regenerative Medicine, the difficulty is that the process requires deriving stem cells from unfertilized mouse embryos, meaning the cells only contain one set of chromosomes. In diploid cells, there are two sets of chromosomes that align and negotiate the genetics of the resulting organism. Called, this is where a dominant gene may be marked active, while a recessive gene is marked inactive.
"Genomic imprinting is frequently lost, meaning the information about which genes should be active disappears, in haploid embryonic