Gene-edited insects: Small yet powerful

Produced by: Science Popularization China

Author: Earth's Gravity (Popular Science Creator)

Producer: China Science Expo

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Insects have long been used in commercial feeds for poultry, fish, pigs, cattle and pet food, but they are still relatively niche. However, insect farming is increasingly becoming a potential new market due to its important role in reducing food waste, providing high-quality animal feed, and providing oil and fertilizer, and as biotechnology tools emerge and breeders are gradually increasing insect production.

Insect species

(Image source: Wikipedia)

In the past few years, companies producing black soldier fly larvae (Hermetia illucens) and yellow mealworms (Tenebrio molitor) have made significant progress , paving the way for insect products to enter European and Asian markets.

Insect factories are expanding, with some companies using gene editing to improve protein quality and speed up the insect hatching and growth process. If this trend continues, the insect protein market is expected to reach $1.14 billion by 2027.

Black soldier fly

(Image source: Wikipedia)

An insect feed company abroad was founded by three doctoral students who developed a technology that induces newborn larvae to enter a state of suspended life through environmental conditions to extend the shelf life of the larvae during transportation. Just like hibernation, this is a reversible "larval dormancy" stage.

The company is also using the gene-editing technology CRISPR-Cas9 to improve the nutritional content of black soldier fly larvae strains. The company has successfully used about 150 genes that control metabolism to obtain larger larvae, longer larval stages and greater stress resistance.

Black soldier fly larvae

(Image source: Wikipedia)

One gene they edited is a key regulator of the molting process from larvae to pupae, and when tweaked, the resulting larvae were 50 percent larger than unedited ones. They also manipulated another gene to reduce the chitin content of the insects' exoskeleton, making it softer— making the insects more suitable for use as aquaculture feed.

Another company is genetically modifying black soldier flies to enable them to be used as biofuel, as their larvae are rich in lipids that can be used as a sustainable alternative to crop oils.

Another advantage is that the farming of black soldier flies is a circular economy, as they can be reared on different substrates such as food waste and feces. However, black soldier flies have not been used commercially in food to date, as the market is more inclined towards feed production.

However, identifying black soldier flies with desirable mutations is time-consuming and can become a bottleneck, so the company has developed a technique that allows DNA to be extracted and screened at hundreds of individuals per day. The company also plans to add phenotypic markers, such as eye color, to speed up screening further, as well as gene knockdown techniques, such as RNA interference (RNAi), to expand the characterization of black soldier flies.

Meanwhile, an insect genetics company based in the UK is more focused on selecting varieties with the best breeding characteristics.

The scientists first collected physical and environmental parameters from insect populations, selecting for those with traits such as faster development and more egg laying. This approach allowed them to separate favorable genetic traits from possible environmental variables, as sometimes insects may be more advantageous because they have more food or are kept at higher temperatures, rather than because they have a genetic advantage.

In addition to black soldier flies, the larvae of another beetle, commonly known as mealworms, have also begun to become the focus of scientific researchers.

Mealworms (larvae of Tenebrio molitor) are commonly used in aquaculture and pet food. But in addition to providing high-quality nutrition for animals as animal feed and plant fertilizer, mealworms also excel in digestion, including the biodegradation of plastic waste. It is the only known organism that can degrade polystyrene in its intestines.

Mealworms are larvae of beetles of the genus Mealworm

(Image source: Wikipedia)

Genomic tools can be used to exploit the potential of mealworms in the most efficient and scalable way. Through selective breeding, scientists target key traits such as body weight and development time, track their heritability, and monitor the genomic diversity of the breeding pool.

In addition, scientists are developing a CRISPR conceptual toolkit for producing customized proteins in insects.

Because of the high-protein properties of mealworms, they have been added to some luxury dog ​​food brands in the United States.

Mealworms are a common pet food

(Image source: Wikipedia)

Due to the huge potential of mealworms in the food industry, an emerging company has set up a new vertical insect farm that can produce several tons of mealworm products every year. The company also launched the world's first high-density gene chip for insect breeding in 2023.

The so-called high-density gene chip is a microarray technology used to analyze and detect genomic information. It is a small and thin solid surface that contains thousands or even more DNA probes or nucleic acid fragments, each of which represents a specific gene or genomic region. These probes can be used to detect gene expression levels, gene variations, single nucleotide polymorphisms (SNPs) and other gene-related information in samples.

The insect breeding gene chip contains 679,205 single nucleotide polymorphisms, covering more than 99% of the coding region of mealworms. It can help scientists identify genes related to their characteristics of interest , such as growth performance, reproduction or disease resistance. The company plans to expand the production of the new chip to help other insect breeding institutions.

Overall, thanks to the efforts of these companies and gene-editing tools, insect farming is gradually emerging in the global food economy as an important alternative source of animal protein.