Central America’s Columbian Mammoths Reveal Surprising Genetics

Recent research has uncovered intriguing genetic information about the Columbian mammoth, challenging long-held assumptions about its lineage. A team of researchers has successfully extracted DNA from mammoth bones found in the Basin of Mexico, near Mexico City, revealing that these ancient creatures form a distinct genetic cluster. This discovery has significant implications for understanding the evolution of mammoths in Central America.

Traditionally, mammoths have been categorized primarily as large, hairy relatives of modern elephants, with the most recognized species being the woolly mammoth and the Eurasian steppe mammoth. The Columbian mammoth, which roamed as far south as Central America, has often been viewed as a puzzling outlier in this narrative. Genetic analysis has typically suggested that it was either a descendant of the steppe mammoth or a hybrid of the woolly and steppe species. However, the new findings indicate a more complex genetic history.

The research team, comprising Mexican and European scientists, focused on mitochondrial DNA, which is typically more resilient in warmer climates compared to nuclear DNA. The Basin of Mexico has yielded numerous mammoth remains, with over 100 individuals discovered during construction projects, including efforts to build Mexico City’s international airport. From a total of 83 samples tested, the researchers successfully obtained 61 new mitochondrial genomes, with 28 of these being analyzed for quality.

By constructing a family tree from the genetic data, the researchers identified three distinct groupings within the Columbian mammoths from this region. Notably, these mammoths clustered together, but their placement on the broader family tree was unexpected. While the Mexican mammoths had woolly mammoths on either side of their lineage, some Columbian mammoths from further north were found to be more closely related to woolly mammoths than to their Mexican counterparts.

This finding suggests a geographical influence on genetic similarities, rather than strict adherence to species classification. The researchers propose two potential explanations for this phenomenon. Firstly, the Columbian mammoth may be the result of multiple hybridization events occurring across different locations. This would imply that the Columbian mammoth is less a single species and more a collection of hybrid populations, potentially isolated by geographical barriers.

The alternative hypothesis, which the research team leans toward, posits that the North American woolly mammoth population possessed various distinct mitochondrial lineages. Consequently, when hybridization occurred, these lineages could have contributed to the genetic makeup of what became the Columbian mammoth.

Despite these intriguing insights, the research highlights the limitations of relying solely on mitochondrial DNA for a comprehensive understanding of the Columbian mammoth’s genetics. The success rate of obtaining usable mitochondrial DNA is low, suggesting a need for future studies that focus on the nuclear DNA of Columbian mammoths that lived in cooler northern regions, where DNA preservation is more likely.

As researchers continue to explore the genetic history of these ancient creatures, the findings from the Science journal in 2025 emphasize the necessity of a broader perspective in studying mammoth evolution, particularly in the context of geographical and environmental influences on their genetic diversity.