The second-largest genome ever sequenced belongs to a small but fascinating creature. Called “xiao qiang” or “little mighty” in China, the American cockroach has a genome larger than that of humans.
It’s genetic code holds the secrets to how these insects can survive on so many different types of food and in such unfriendly habitats, or even how it can survive for a week without a head and grow replacement limbs.
Researchers at South China Normal University in Guangzhou sequenced the genome of the hardy insect and published their findings in Nature Communications last week.
They found that the groups of genes related to the immune system, sensory perception, detoxification, and growth and reproduction were all enlarged, helping to explain how cockroaches are able to live in so many different environments — and why it’s so hard to kill them.
“It’s a tiny pest, but has very strong vitality,” Sheng Li, the lead author of the paper and entomology professor, told the New York Times.
Since sequencing the first human genome, which took more than a decade and nearly $2.7 billion, medical researchers have found ways to make organisms resistant to disease. Also, CRISPR technology has moved the medical field toward cheap and and easy DNA editing.
Scientists are looking to species like the American cockroach to learn about how traits that make them incredible adapters and stubborn survivalists are encoded in their DNA. Compared to other insects, the American cockroach genome is larger than any known genome sequence except locusts.
Here are a variety of ways this information about roaches can help humans:
The researchers found that American cockroaches have more than 1,000 genes that help them read chemical cues in their environment.
More than 300 of these genes relate to sensing bitter tastes, giving cockroaches plenty of information about which foods are and are not safe to eat. The bugs also have genes that allow them to withstand toxic environments and a higher number of enzymes that break down toxins in addition to their stronger immune systems.
The genes that show why cockroaches are so hardy also give clues about how to get rid of them.
Scientists manipulated more than 20 genes related to the immune system, reproductive system, and development, revealing damaging effects on the insects. This could show a path toward creating new pest control methods, similar to the genetically embedded insecticides Monsanto has developed.
The American cockroach will regenerate lost limbs. By amputating limbs during their research and monitoring their regrowth, scientists found that genes in the cockroach’s DNA prompt healing and regeneration.
Cockroaches have long been used in traditional Chinese medicine for treating cuts and burns, but researchers will study how the insects generate new tissue in hopes of unlocking future medical applications for humans.
“We’ve uncovered the secret of why people call it ‘xiao qiang,’ ” Li said. “Now we want to know the secrets of Chinese medicine.”
By studying cockroaches and termites, scientists hope to uncover the genetic origins of eusociality, which causes organisms to work together and cooperate in dividing labor.
Termites, which recent research shows are more closely related to cockroaches than originally thought, developed this trait much earlier than insects like bees and ants.