Pando is the largest living thing on earth. Weighing 6,000,000 kilograms, it is about as heavy as a thousand African elephants or forty blue whales. When you enter Pando, you may hear a soothing sound like the beating of tiny wings. Pando is a grove of 47,000 quaking aspen trees, named for the distinct sound their leaves make in the wind. Every tree in the forest is genetically identical. This is because they are all parts of a single being, connected underground by a huge root system.
Hence, geneticists worldwide have called for a moratorium on human germline trials. Critics say that gene editing technology has not yet been developed or tested sufficiently for use on human embryos. We simply do not yet know the long-term effects of genetic modification using CRISPR.