Gecko's amazing wall-walking talent is all in the genes

[November 25, 2015]  By Will Dunham
 
 WASHINGTON (Reuters) - Geckos boast one of the most impressive talents of any animal: the ability to scamper up a smooth wall or across a ceiling with ease. How do they do it? Well, it is all in the genes.

Scientists on Tuesday said they have sequenced the genome of the gecko species Gekko japonicus, or Schlegel's Japanese gecko, and found the genetic underpinning of the lizard's gravity-defying feat.

The gecko walks up walls and across ceilings thanks to sophisticated adhesive foot pads comprised of tiny hairlike structures known as setae covering the base of its toes. These setae are composed predominantly of beta-keratin, a protein found in reptiles that is in the keratin family. Keratin is the substance in human fingernails and hair.

The scientists found in Gekko japonicus an expansion in the genes related to beta-keratin, accounting for the gecko's ability to generate its setae. No such expansion exists in the genomes of other reptiles lacking the ability to walk on smooth vertical or ceiling surfaces. All told, 35 such genes were identified.

"The findings provide a robust genetic basis of adhesive setae formation," said Xiaosong Gu, a neuroscience and regenerative medicine researcher at Nantong University in China.

A gecko can cling to nearly any type of surface, whether it is hard, soft, smooth or rough. The new findings may aid the development of "bio-inspired adhesive technologies" mimicking the gecko's adhesive mechanism, Gu added.

Schlegel's Japanese gecko, about 4-1/2 inches (12 cm) long, is a nocturnal insectivore found in Japan and eastern China. Its climbing abilities help the gecko catch prey and flee predators.

Gecko foot pads are no recent development. Geckos have existed since the age of dinosaurs. Scientists in 2008 announced the discovery in Myanmar of the remains of a gecko with adhesive pads preserved in amber dating to 100 million years ago.

The study also revealed the genetic foundation of the gecko's sharp nocturnal vision and its ability to regenerate its tail, Gu said.

Geckos can shed their tail to escape an attacking predator and then later regenerate it. About 155 genes related to regenerative abilities were identified, providing fresh insight into regenerative biology, Gu said.

The size of the gecko's genome was the largest of any reptile species whose genome has been sequenced, Gu said.

The research was published in the journal Nature Communications.

(Reporting by Will Dunham; Editing by Sandra Maler)

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