For remains from tropical or subtropical regions, where warm and humid conditions accelerate biological degradation, the petrous bone’s protective qualities become even more important.

DNA preservation in tropical soils is generally poor; many ancient specimens from the tropics have yielded no usable genetic material despite extensive extraction attempts.

The success of the 2025 Colombia study in recovering genome-wide data from seven Preceramic individuals at 6,000 years before present suggests that the cool, high-altitude conditions of the Bogotá Altiplano provided preservation conditions significantly better than those in tropical lowland regions.

The combination of high altitude (reducing temperature), relatively low humidity compared to lowland tropical environments, and the specific soil chemistry of the Altiplano may have combined to create conditions favorable for DNA preservation over millennia.