A Smithsonian-led team with Texas A&M researchers has traced ancient human movement through the genomes of Central American avocados. DNA signals preserved in leaves from Nicaragua reveal that, roughly 5,000 years ago, migrating people moving north from South America carried large avocado seeds into Central America’s humid lowlands. There, they hybridized with local plants, reshaping today’s diversity of landrace avocados.
The study focuses on Persea americana populations across Nicaragua, Honduras, and southern Mexico. Researchers extracted and analyzed DNA from 47 native landraces, comparing their genetic patterns with previously published data from more than 200 avocado lineages. The resulting phylogenetic relationships show clear geographic structure rather than random mixing across the region.
In southern Mexico, the samples cluster closely with ancestral highland populations and include links to commercial-like lineages. By contrast, Nicaragua’s lowland landraces connect genetically to groups found farther south, including coastal Colombia. This genetic continuity supports the interpretation that human transfers of local varieties repeatedly occurred along migration routes, rather than the result of independent, isolated domestication events.
To avoid treating avocados as purely biological objects, the team integrated ethnobotanical fieldwork. Farmers and gardeners helped map cultivation practices and highlighted how traditional management maintains robust local trees. The researchers also recorded adaptation patterns relevant to disease and climate resilience, including the importance of local lowland growing conditions.
A major implication is crop vulnerability. More than 80% of global commercial production relies on a single clonal variety, Hass, propagated through grafting. Clonal planting creates low genetic variability at the farm scale, making outbreaks and environmental shifts easier to spread and harder to contain.
Wann, an archaeobotanist who conducted the research as a museum fellow and later pursued a doctorate at Texas A&M, argues that Central America’s lowland reservoirs of genetic diversity may act as a practical defense strategy. Specifically, landraces appear better suited to warmer and wetter climates and may offer genetic tools for breeding programs targeting disease tolerance.
The paper also suggests a conservation urgency: some growers in Nicaragua are replacing older landraces with commercial trees, shrinking the pool of locally adapted diversity. Because genetic variation can buffer future climate or pathogen pressure, losing landraces could reduce avocado resilience as a species.
Overall, the work reframes avocado diversity as both a biological system shaped by selection and a cultural artifact carried by people. The ancient migrations recorded in DNA are now pointing to a modern necessity: safeguard landraces that commercial orchards alone cannot replicate.
Article Title: Ethnobotanical and genetic assessments of Central American avocado landraces reveal novel sources of biodiversity and ancient migration patterns
News Publication Date: 22-Jul-2026
Web References: https://nph.onlinelibrary.wiley.com/doi/10.1002/ppp3.70236
References: 10.1002/ppp3.70236
Image Credits: Kevin Wann, 2024 Missing Migrants Project
Keywords: avocado landraces, ancient migration, DNA phylogenetics, ethnobotany, crop diversity, clonal propagation, conservation genetics, Persea americana
