Scientists Stunned at First Live Birth of ‘Chimeric’ Monkey

The embryos, originating from the same species of monkey (crab-eating macaque), displayed genetic differences, contributing to the unique nature of the offspring.

Chimeras, defined as animals containing cells from two or more organisms with distinct DNA, offer valuable insights into embryonic development. In this study, the baby monkey exhibited a substantial proportion of donor cells, averaging 67% across 26 different tissue types. 

This achievement holds great promise for various applications, ranging from enhancing our understanding of conditions like motor neurone disease to aiding in the conservation of endangered species.

Senior author Zhen Liu, affiliated with the Chinese Academy of Sciences, emphasized the significance of this achievement in the field, stating, “This is a long-sought goal in the field.” 

He highlighted the potential for generating more precise monkey models for studying neurological diseases and other biomedical research.

While previous attempts at creating monkeys in laboratories involved donor cells, these efforts fell short of producing true chimeric animals. The key distinction in this study lies in the remarkably high contribution of donor cells, forming intricate structures and comprising a significant part of the monkey’s tissues throughout the body.

Stem cells, serving as the body’s raw materials for generating specialized cells, played a crucial role in the experiment. The researchers utilized stem cell lines from a seven-day-old embryo, injecting them into four to five-day-old embryos. Subsequently, these embryos were implanted into female macaques, resulting in 12 pregnancies and six live births.

Analysis of the live-born baby monkey revealed donor stem cells in 26 different tissue types, ranging from 21% to up to 92%. Additionally, a miscarried fetus displayed substantial chimerism, with stem cell-derived cells observed in various organs.

Addressing ethical considerations, the researchers asserted that their work adhered to national ethical regulations in China. Moving forward, the researchers aim to explore the mechanisms underlying the survival of embryos in host animals. 

Professor Mu-Ming Poo emphasized the importance of improving the health and longevity of chimeric monkeys for the development of effective monkey models in future research endeavors.