Latitudinal genetic diversity gradients steepen toward the poles

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint. You must log in to post a comment. There are no comments or no comments have been made public for this article. This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint. Add a Comment You must log in to post a comment. Comments There are no comments or no comments have been made public for this article. Latitudinal biodiversity gradients are among the best-described biogeographic patterns. However, there is little agreement on whether genetic diversity, the most fundamental level of biodiversity, is also latitudinally distributed. The confusion about the distribution of genetic diversity at biogeographic scales stems in part from the fact that genetic diversity gradients have been described for multiple types of genetic diversity, with good reasons to expect patterns to vary with the component of genetic diversity examined. Genome-wide diversity varies both within and across species. Thus, nuclear genetic diversity gradients might arise due to the existence of parallel latitudinal gradients within species, or due to species turnover and differences in species-level genetic diversity across latitudes. We used a compilation of nuclear genetic data from 100 mammal species across 1,426 locations to test for latitudinal genetic diversity gradients using Bayesian hierarchical regressions. We detected no general latitudinal genetic diversity gradients within or across species. However, the direction of within-species genetic diversity gradients was associated with species attributes. Notably, the slopes of intraspecific latitudinal gradients became increasingly positive for species distributed at higher latitudes. Interactions between species-level and population-level processes appear to shape the biogeography of genetic diversity. https://doi.org/10.32942/X2RP9R Evolution, Genetics, Population Biology latitudinal diversity gradient, biogeography, biodiversity, Population genetics, macrogenetics, Mammals Published: 2025-07-22 18:15 Last Updated: 2025-07-22 18:15 CC BY Attribution 4.0 International Conflict of interest statement: None Data and Code Availability Statement: Open data/code are not yet available. Language: English