The Chinese scientists have reportedly carried out the first ever experiment for bringing alteration in the DNA of human embryos.

The controversial technique used by the scientists to alter the DNA of human genomes is known as CRISPR/Cas9. It represents a biological version of the “find and replace” function of a word-processing program. The researchers introduce the enzymes that bind to a mutated gene at the first occasion and then replace or repair it.

According to the reports, the scientists have planned or presently carrying nearly half a dozen experiments on human eggs or embryos with the help of CRISPR technology in order to correct the genetic defects like those resulting into the BRCA1 breast-cancer gene or the cystic fibrosis.

The researchers gathered 86 early-stage, non-viable embryos for the study and injected them with the gene-editing tool ‘CRISPR/Cas9’.

The gene-editing technique has been used in many previous studies for altering genes in the cells of both humans and animals.

For the study, the researchers targeted a gene called HBB and tried to replace it with new genetic matter. The gene is linked with the potentially deadly blood disorder called beta-thalassaemia.

The researchers were able to successfully spliced DNA in 28 of the embryos using CRISPR/Cas9, but they were able to replace the gene in just fraction of them.

The development has ignited a huge outcry in the international science community which is warning against the human genome alteration citing various concerns, including the ethical one.

The China-based study was published last week online in journal Protein & Cell.

Junjiu Huang, study lead author from Sun Yat-sen University in Guangzhou told journal Nature during an interview that both journals have rejected the paper, partly over the ethical causes.

Edward Lanphier, chief executive of Sangamo BioSciences Inc in California, said, “There have been persistent rumors of this kind of research taking place in China. This paper takes it out of the hypothetical and into the real.”

Lanphier is among the group of scientists who had in March called for a global moratorium on such kinds of experiments on human genome.

A note in Protein & Cell shows that the research paper was received on March 30 and then approved on April 1. After the paper was rejected by journals Nature and Science over ethical concerns, a paper describing the findings was published on April 18 online in the journal Protein & Cell.

The scientists are of the belief that any form of outside disturbance in the composition of DNA of human eggs, sperm, or embryos could lead to the production of unknown effects on future generations. These unknown effects may be advantageous or disadvantageous both.