Warming temperatures can impact animals' reproduction, survival: Studies

New Delhi, Sep 5 (PTI) Two studies have found that extreme temperatures can change how a species reproduces, with one reptilian species becoming more resilient to climate change, while the other displaying a 'sex reversal' with a biological male growing into a functional female.

Findings highlight that temperature not only impacts climate, but can also change how life is propagated, having profound implications for an increasingly warmer future, researchers said.

The team, including researchers from the Autonomous University of Barcelona in Spain, said that driven by human activity in the form of contamination and climate change, including greenhouse gas emissions and extreme temperatures, biodiversity is disappearing at an alarming rate.

However, how the changing environment directly affects reproduction and survival of species is not clearly known, they said.

One of the studies, published in PLOS Genetics, looked at the Guibe's ground gecko -- a lizard species native to the warm ecosystems of Madagascar in Africa.

The researchers found that in extremely hot conditions, the lizard species showed an increase in 'recombination' -- a process which creates genetic diversity and heightens a species' chances of adapting to a changing climate and, therefore, is fundamental for the propagation of a living being.

The Guibe's ground gecko (scientific name 'Paroedura guibeae') also displayed a greater DNA fragmentation and changes in chromosomal structures, revealing that temperature not only affects gene expression -- behaviour of a species resulting from how its genes interact with the surrounding environment -- but also how information in genes is passed on through generations.

"This study helps us understand that global warming not only affects the climate, but also influences the adaptation mechanisms of animals to survive," co-author Laura Gonzalez Rodelas, a researcher from the Autonomous University of Barcelona, said.

The authors wrote, "Our findings show the presence of hyper-(crossovers) spermatocytes in individuals exposed to both high and low temperatures." The second study, published in the journal GigaScience, focused on the central bearded dragon ('Pogona vitticeps'), a lizard species typically found in Australia's arid and semi-arid regions.

The central bearded dragon is known to be capable of changing sex if eggs are incubated at high temperatures.

'Temperature-induced sex reversal' allows a biological male individual to develop into a functional female, and genome sequencing can help identify genes critical to sex determination and understand how the species' environment can change gene behaviour that define an individual's sex, the researchers said.

"This new genome will be a fundamental resource in facilitating and accelerating research on the reproductive particularities of this species, as well as for comparative studies with other reptiles," co-author Laia Marin Gual, a researcher from the Autonomous University of Barcelona, said.

The study says, "The central bearded dragon (Pogona vitticeps) is widely distributed in central eastern Australia and adapts readily to captivity. Among other attributes, it is distinctive because it undergoes sex reversal from ZZ genotypic males to phenotypic females at high incubation temperatures." High-quality genome sequencing "will serve as a resource to enable and accelerate research into the unusual reproductive attributes of this species and for comparative studies across the (lizard species) and reptiles more generally," the authors said. PTI KRS KRS KSS KSS