Genetic rock star

Modern research into the axolotl began in 1864 after a shipment of 34 arrived in Paris from Mexico. Thousands more were then bred as scientists across Europe marvelled at their strange appearance and ability to breathe with both lungs and gills.

Researchers later discovered that axolotls can also absorb oxygen through their skin — making them particularly vulnerable to dirty water — and regenerate amputated limbs and damaged body tissue, creating intense interest in their genes.

Earlier this year, a team of scientists in Germany said they had mapped the complete axolotl genome, revealing it to be 10 times longer than the human genome, which gives researchers more scope to pinpoint the mechanisms for regeneration.

‘‘You can actually take a primordial piece of the tissue that’s going to form its eye and transplant it into the space around the gut and the axolotl will regenerate and form a whole eye there,’’ said Randal Voss, a University of Kentucky scientist and director of the world’s largest axolotl laboratory.

But whether they have a future outside the laboratory will largely depend on whether Xochimilco’s booming tilapia and carp populations can be controlled.

The fish were introduced in the 1970s by the government as part of a nutrition programme, but their taste for axolotl eggs and juveniles was not considered.

Industrialscale fishing earlier this year removed tonnes of them from Xochimilco, but the effort has run out of funding.

Claudia Sheinbaum, set to take over as Mexico City’s mayor in December and herself a scientist, said recently she wanted the capital’s water infrastructure overhauled, and the raw sewage that pollutes the