Abstract
We quantified C-band size variations of the No. 2 chromosomes in the Japanese house mice, Mus musculus, including wild-caught mice and their F1 offsprings produced by crosses between them. The sizes of C-bands were expressed by their relative lengths as a positively stained region / a negatively stained region by Cbanding in each of the No. 2 homologue. In 11 of the 16 mice examined by one-way ANOVA, the relative lengths of the C-bands were statistically polymorphic in the No. 2 homologue with variable C-band sizes at p=0.05. On the other hand, the remaining five individuals carried slightly different relative lengths without significance, which is considered as a homomorphism. Usually, heterochromatin is thought to be evolutionally neutral without strong selections, and it is considered that the polymorphic state is a frequent phenomenon of the Japanese house mice without any cytogenetically deleterious effects. In addition, the mean of the difference between the relative lengths in the No. 2 homologue ranged from 0.046 to 0.210 in the 11 individuals showing polymorphic state and from 0.032 to 0.044 in the five showing homomorphic state. Thus, a mean index of approximately 0.045 is considered to be the boundary dividing polymorphic and homomorphic states.
Original language | English |
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Pages (from-to) | 459-463 |
Number of pages | 5 |
Journal | Cytologia |
Volume | 81 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2016 |
Keywords
- C-band
- Japanese house mice
- Polymorphism
- Quantification