Giant Island Mice Exhibit Widespread Gene Expression Changes in Key Metabolic Organs

Giant island mice, the largest wild house mice globally, exhibit widespread gene expression changes in key metabolic organs, providing insights into the genomic basis of extreme body size evolution. Researchers compared gene expression patterns between Gough Island mice and mainland mice using RNA-seq on gonadal adipose depot, hypothalamus, and liver tissues. They identified significant differential expression in 20% to 50% of detected transcripts, with fold changes of at least 2× in each organ. Among the findings, 73 candidate genes for extreme size evolution were pinpointed by integrating gene expression data with quantitative trait loci, whole-genome sequencing, and regulatory elements. Functional enrichment analyses suggested that cell cycling, mitochondrial function, signaling pathways, inflammatory response, and nutrient metabolism contribute to weight accumulation in these mice. The study highlights the rapid evolutionary changes in metabolic organs accompanying gigantism on Gough Island.

Nolte, M. J., Jing, P., Dewey, C. N., & Payseur, B. A. (2020). Giant Island Mice Exhibit Widespread Gene Expression Changes in Key Metabolic Organs. Genome Biology and Evolution, 12(8), 1277–1301. https://doi.org/10.1093/gbe/evaa118