This new species of lizard evolved in a laboratory | Smart News

Aspidoscelis neavesi, a species like no other.
Photo: Pierre Baumann

Aspidoscelis neavesi, a new lizard that looks a bit like the anoles that hang out on Florida porches, isn’t just any ancient species recently discovered. Rather than evolving in nature, A.neavesi was created in a laboratory by breeding two related species of lizards. Normally, hybrid animals are sterile, but like Carl Zimmer reports for the New York Times, A.neavesi defied this biological expectation and began to reproduce in the laboratory, not by mating, but by cloning.

New species typically evolve over thousands of generations, Zimmer says, although in recent years scientists have begun to realize that, in rare cases, hybridization could represent a viable route to establishing a new animal. . Some whiptail lizards (a species found in the southern United States) have genes that seem to come from two different species, and they only produce female offspring. Females give birth to females – a process called parthenogenesis – by duplicating their chromosomes. The scientists, writes Zimmer, have concluded that “sometimes individuals of two different species of whiptail lizard interbreed and their hybrid offspring carry two different sets of chromosomes.” Zimmer:

In a way, this triggers a shift to parthenogenesis. Female hybrids begin to produce distinct clones of either parent species. In other words, they instantly become a new species in their own right.

But it gets even weirder. Some species of whiptail lizards carry three sets of genes, rather than two… The weirdness doesn’t end there. In 1967, a Harvard graduate student named William B. Neaves was looking for whiptails around Alamogordo, NM, when he found one with four sets of chromosomes.

In an attempt to recreate this natural experiment, the researchers collected parthenogenic females with three sets of genes from the field in New Mexico and introduced them to closely related males in the lab. As Zimmer reports, scientists found that the offspring of these lizards actually had four sets of chromosomes. Females with four sets of genes then began to clone themselves, eventually producing a colony of 200 lizards, which continues to grow.

After confirming that they had created a new species, scientists named it Aspidoscelis neavesi, after William B. Neaves, who led the study and discovered four-chromosome lizards in 1967. Some scientists, however, believe that biology needs a whole new term to describe A.neavesi, since the entire species is made up of clones. Something like “hybrid clones,” one researcher told Zimmer, would be a more accurate descriptor.

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