Syndicate content

Cockroach Genome Sequence Analysis Reveals Why These Insects Are Virtually Indestructible

They can regrow lost legs. They make their own antibiotics. And they have an almost supernatural sense of smell. Now, Chinese researchers have sequenced the genome of the American cockroach and discovered these abilities are all in the DNA. They report on this in an article published online on March 20, 2018 in Nature Communications. The open-access article is titled “The Genomic and Functional Landscapes of Developmental Plasticity In The American Cockroach.” The American cockroach, known scientifically as Periplanta Americana, has an enormous genome, Dr. Shuai Zhan and colleagues at the Chinese Academy of Sciences in Shanghai, found. And it’s more closely related to termites than it is to German cockroaches, despite their shared unsanitary habits and ability to horrify homeowners and terrorize tenants. Cockroaches spread germs and can aggravate asthma and allergies. "The harm of American cockroaches is becoming more serious with the threat of global warming," Dr. Zhan's team wrote. “Our study may shed light on both controlling and making use of this insect.” And the DNA explains why they are so prolific. When under stress, females can lay unfertilized eggs that will hatch in a process called parthenogenesis or “virgin” reproduction. The team found genes that explain how this can happen. Cockroaches can also survive terrible injuries. "The American cockroach has a strong capability of limb regeneration during the nymph stages, which is the main reason to call it ‘Xiao Qiang’ in China,” the researchers wrote. The name translates as “little mighty one," and the team found genetic pathways that underlie the process. DNA can also explain cockroaches’ noxious habits. "Cockroaches generally live in moist and unsanitary areas and are particularly fond of fermenting foods; thus, they have numerous opportunities to be exposed to microbes and pathogens," the team wrote. The insects have extra genes related to chemoreception, or smell. And the insects have evolved sophisticated ways to deal with their dirty environments. Their cells respond to infection with bacteria and fungi by secreting antimicrobial peptides that go into the hemolymph — the juice that squirts out when you stomp on a roach. Plus, cockroaches have natural detoxification mechanisms. Targeting these genetic pathways might be a better way to kill the pests, the Shanghai researchers suggested. It also might be possible to exploit these properties, they said. "Beyond serving as a pest, this cockroach is also important in traditional Chinese medicine, well documented in Chinese medical encyclopedias," they wrote. "Moreover, its ethanol extract has been developed as a prescribed drug (Kang Fu Xin Ye) for wound healing and tissue repair." Understanding the genetic secrets could help scientists replicate the cockroach’s superpowers, they said.

[Press release] [Nature Communications article]