GENE EDITING EMBRYOS
1. Context
A Chinese scientist stirred up a hornet’s nest by announcing the birth of gene-edited twins in 2018. A new study warns of the consequences of deploying a technology that is still less understood.
Deleting harmful disease-causing mutations by gene editing could be counterproductive. It could create more problems than it solves
2.Important Observations
- CRISPR can target and edit DNA at precise locations. CRISPR to make the embryos resistant to the human immunodeficiency virus
- Gene editing can be divided into two classes. One involves changing genes in human cells. This method does not alter reproductive cells, such as sperms or eggs. It can be used to treat diseases caused by mutations.
- The second method alters the genome of human embryos. These altered genes can be passed on to future descendants, raising ethical concerns
- The break sites are repaired by human embryos. They do so by copying genetic information from the normal copy of the gene onto the altered strand of the DNA
- CRISPR could lead to extensive gene copying from one parent to the other
- Humans possess two versions of a particular gene received from each parent
- If a child gets a recessive disease-causing gene from one parent and a dominant healthy version of the same gene from the other, they could still be protected.
- The extensive copying of genetic information from one parent to another due to CRISPR could give rise to two mutant copies of the disease-causing gene in the embryo.This significantly increased the risk of diseases
3.Misdiagnosis
The gene-edited embryo should be tested before it is transferred into the uterus. Scientists do this by collecting a small sample from a few or even a single cell
It is then multiplied millions of times using whole genome amplification
Whole genome amplification is a technology that helps increase the amount of DNA samples
The researchers proposed an alternative method that uses stem cells from gene-edited embryos
Stem cells can develop into any functional cells, such as skin cells, muscle cells, liver cells or brain cells
As these stem cells grow indefinitely, they can provide ample DNA material for testing
Source: DownToEarth
