Who is the ancestor of modern mice? - briefly
The direct predecessor of today’s house mouse (Mus musculus) was a Pleistocene‑age Mus species that lived in South Asia. Genetic evidence dates its split from close relatives to roughly one to two million years ago.
Who is the ancestor of modern mice? - in detail
The progenitor of contemporary Mus species emerged within the Murinae subfamily during the late Miocene, approximately 10–12 million years ago. Fossil remains attributed to early members of the genus Mus have been recovered from European and Asian deposits, indicating a broad geographic distribution before the diversification of modern lineages.
Genetic analyses of extant house mouse subspecies (M. musculus domesticus, M. m. musculus, M. m. castaneus) converge on a common wild ancestor that inhabited the Indian subcontinent. Divergence estimates place the split between this ancestral population and its closest extant relatives, such as Mus spretus and Mus spicilegus, at roughly 1–2 million years ago. The ancestral genome exhibits signatures of rapid adaptation to human‑associated environments, a process documented through comparative sequencing of ancient DNA extracted from archaeological specimens.
Key points summarizing the evolutionary background:
- Early Murinae diversification – Late Miocene radiation produced the first recognizable Mus fossils.
- Geographic origin – Molecular clocks locate the ancestral population in South Asia, with subsequent expansion into Europe and the Americas via human trade routes.
- Phylogenetic relationships – Closest living relatives (M. spretus, M. spicilegus) share ~95 % genomic similarity, reflecting a recent common ancestor.
- Adaptation timeline – Genomic evidence shows selection for traits linked to commensalism (dietary flexibility, reproductive rate) occurring within the last 10 kyr.
The cumulative fossil record, combined with high‑resolution genomic data, identifies a South Asian wild mouse lineage as the direct forebear of today’s house mouse, from which all domesticated and laboratory strains descend.