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CRISPR gene editing realizes sex selection, and 100% produces male or female offNature Communications: CRISPR gene editing realizes sex selection
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Nature Communications: CRISPR gene editing realizes sex selection, and 100% produces male or female offspring.
You may not know that there are about 7 billion male chicks in the world every year as soon as they hatch, and they are “disposed” because they can neither lay eggs nor have their meat quality as good as hens.
In addition, dairy farms want their cattle to give birth to as many cows as possible, which results in millions of bull calves being “processed” every year around the world. Under normal circumstances, a sex ratio of 1:1 leads to a large number of animals of the sex that are not required to be processed and wasted.
The same is true for scientific research. Many studies only require experimental animals of a specific sex.
For example, breast cancer studies often only require female mice, while prostate cancer studies require only male mice. This leads to animals of another sex. Was wasted.
In the past 5 years alone, there have been approximately 25,000 papers on mice of a specific sex.
Therefore, the production and culling of animals of a specific sex has caused a great burden both ethically and economically.
If we can only produce animals of a specific sex that we need from the beginning, it will obviously solve this dilemma to a large extent.
Recently, researchers from the Francis Crick Institute and University of Kent published a research paper titled: CRISPR-Cas9 effectors facilitated generation of single-sex litters and sex-specific phenotypes in Nature Communications .
The research uses CRISPR gene editing technology and uses mice as a model to develop a synthetic and lethal two-component CRISPR-Cas9 strategy that can allow mice to produce 100% of all males or all females.
More importantly, the technology may also be applicable to other vertebrate species and provide solutions to ethical and economic problems faced in laboratory research and agricultural production.
As we all know, the CRISPR-Cas9 gene editing system consists of two parts: Cas9 enzyme used to cut DNA and sgRNA used to identify targeted DNA sequences .
These two components cooperate to achieve targeted cleavage of specific DNA sequences, thereby achieving gene editing.
In order to achieve the purpose of allowing mice to produce only offspring of a specific sex, it is necessary to eliminate embryos of one sex.
The research team put the two components of CRISPR, Cas9 and sgRNA, into two parents. Then, they needed to find a molecular target that can effectively eliminate embryos.
This target must be at a sufficiently high level and at the correct level during development. Time expression.
The research team chose the topoisomerase 1 gene ( TOP1 ) , which is the key to cell division. If this gene is deleted, it will cause the embryo to die quickly at a very early stage.
The research team inserted the DNA sequence encoding the sgRNA targeting the TOP1 gene into the genome of female mice, and inserted the DNA sequence encoding the Cas9 enzyme into the Y chromosome of male mice.
Then the two mice mate. When the Y chromosome-carrying sperm and egg are combined, the Cas9 enzyme binds to the sgRNA targeting the TOP1 gene, and then knocks out the TOP1 gene, causing the male embryo to die when there are only dozens of cells. , And eventually only produced female mice.
If the DNA sequence encoding the Cas9 enzyme is inserted into the X chromosome of a male mouse, the opposite result will be produced, that is, only male mice will be produced.
From the experimental results, under normal circumstances, the sex ratio of mice at birth is close to 1:1, and this CRISPR gene editing strategy can achieve 100% of the offspring of male mice or 100% of the offspring of female mice.
I believe that some readers who saw this, began to worry that this method would be used on humans, which would lead to an imbalance in the sex ratio.
In fact, this kind of worry is completely unnecessary .
First of all, gene editing on humans requires strict review, and the application of genetic editing operations that can be inherited in the paper is even more illegal for humans.
Secondly, this method is only suitable for species with many litters and short gestation period. If humans need to adjust the gender at birth, there are simpler and more feasible methods.
Nature Communications: CRISPR gene editing realizes sex selection
(source:internet, reference only)