Does a field mouse have 40 chromosomes? - briefly
The common field mouse (Apodemus sylvaticus) possesses a diploid chromosome count of «40». This number is uniform across the species.
Does a field mouse have 40 chromosomes? - in detail
The diploid chromosome complement of the typical European field mouse (Apodemus sylvaticus) is 48 chromosomes (2 n = 48). This count is established through standard G‑banding karyotype analyses performed on bone‑marrow and fibroblast cultures.
The species belongs to the family Muridae, subfamily Murinae, and differs from the laboratory mouse (Mus musculus), which possesses 40 chromosomes (2 n = 40). The distinction reflects divergent evolutionary pathways within the genus and is corroborated by comparative genomic studies.
Chromosomal structure in the field mouse includes:
- Six pairs of large metacentric chromosomes.
- Four pairs of medium‑sized submetacentric chromosomes.
- Ten pairs of small acrocentric chromosomes.
These morphological categories facilitate identification of homologous chromosomes and enable detection of structural rearrangements.
Karyotypic variation among populations is limited; occasional minor polymorphisms involve pericentric inversions on specific submetacentric pairs, but the overall number remains constant at 48. No documented cases show a reduction to 40 chromosomes in natural field‑mouse populations.