50 years ago, chimeras gave a glimpse of gene editing’s future

Excerpt from the June 1, 1974 issue of Science News

A chimera pig embryo

Advances in genetic engineering over the last 50 years let scientists in 2023 introduce human stem cells into a pig embryo engineered to lack a kidney. The stem cells grew into a new organ made mostly from human cells.


Animal Genes Transplanted to Bacteria — Science News, June 1, 1974

Genes from animals can be combined with genes from bacteria and be put in a bacterium so that the animal genes can replicate in the bacterium…. The technique consists of constructing DNA “chimeras” — molecules that consist of genes from different sources…. Some day the technique may be used to correct genetic defects.


Chimera experiments have moved far beyond bacteria. Advances in gene-editing technology have helped scientists create mouse embryos with a dash of human cells, grow brains that are a mix of rat and mouse cells, and grow mostly human organs in pigs (SN: 5/13/20; SN: 4/25/24; SN: 9/7/23). In March, surgeons at Massachusetts General Hospital in Boston transplanted a genetically modified pig kidney into a living person. The kidney had certain pig genes removed and some human genes added to improve the organ’s compatibility with the human immune system. The man was discharged from the hospital in April. He died in May from a cause unrelated to the transplant, the hospital said.

Abby Wallace is the digital engagement producer at Science News. She has an undergraduate degree in biology from George Washington University in Washington, D.C., and a master’s degree in journalism from the University of Maryland — College Park.

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