Scientists Say: Genetic Engineering

Genetic engineering involves tweaking an organism’s DNA to give it certain desired traits

a cluster of orange blobs that look sort of like baby carrots stand out against a blue background

E. coli bacteria (like those pictured) have been genetically engineered to produce human insulin to treat people with diabetes.


Genetic engineering (noun, “Jeh-NEH-tik En-jeh-NEER-ing”)

Genetic engineering is the act of tweaking a living thing’s DNA to give it certain traits. Plants, animals and microbes whose DNA has been changed this way are called GMOs. That’s short for genetically modified organisms.

An organism’s DNA can be changed in a few ways. A piece of its DNA can be chemically altered or removed. Or, a bit of DNA from another species can be added to or replace a piece of DNA. Such changes can be made to single cells that then multiply. For instance, one microbe with changed DNA can divide and spawn many more with the same genetic change. And a fertilized egg cell with tweaked DNA will grow up into an organism with that same DNA change in every cell of its body. Such GMOs then pass their modified genes on to their offspring. 

Scientists have genetically engineered microbes, plants and animals for decades. For example, bacteria and yeast cells have been engineered to produce insulin. That insulin can then be used to treat people with diabetes. Other modified microbes produce vaccines. Still others make proteins for blood clotting or other medicines.

Crops, meanwhile, have been genetically tweaked to withstand pests. Or resist weed-killing chemicals. That way, farmers can use those chemicals on their land without harming crop plants. DNA changes have also led to more nutritious or faster growing plants.

Some farmed animals, such as salmon, have likewise been engineered to grow up faster. Scientists use other genetically modified animals in labs to study how genes relate to health and disease. And genetically engineered animals can even help prevent the spread of disease. For instance, some mosquitos have been genetically altered so that their offspring die quickly. This could help curb the spread of mosquito-carried diseases like malaria, dengue and Zika.

A different but related technology is called gene therapy. This is the act of tweaking a person’s DNA with the goal of preventing or curing a genetic disease.

In a sentence

Genetic engineering could lead to crops that better withstand the impacts of climate change.

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Maria Temming is the Assistant Managing Editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.

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