Environmental Thermal Stress Induces Neuronal Cell Death and Developmental Malformations in Reptiles

Area of Science:

• Developmental biology
• Ecology
• Climate change science

Background:

• Organismal life history is challenged by global warming, with ectotherms like lizards nearing physiological limits.
• Embryos are particularly sensitive to thermal stress, impacting development and survival.

Purpose of the Study:

• To investigate the effects of current temperatures in natural nesting areas on lizard embryos.
• To identify gene expression changes and developmental abnormalities induced by thermal insult.
• To propose and test a novel developmental hypothesis for thermal-induced malformations.

Main Methods:

• Exposing Anolis sagrei embryos to temperatures experienced in natural nesting areas.
• Analyzing gene expression levels and observing morphological changes.
• Developing and testing a hypothesis on cellular mechanisms of malformation.

Main Results:

• Temperatures in natural nesting areas induced neural and craniofacial malformations in Anolis sagrei embryos.
• Abnormalities ranged from minor facial changes to severe forebrain disruption.
• Early post-oviposition development is highly sensitive to thermal insult.

Conclusions:

• Elevated temperatures pose a significant threat to the viability of ectothermic species.
• A proposed hypothesis suggests cell death in the forebrain and disrupted Hedgehog signaling cause malformations.
• This response to thermal stress may be common among amniote embryos, emphasizing the need for multidisciplinary research on climate change impacts.