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The presence/absence polymorphism and evolution of the p53 pseudogene in the genus Mus
H Ohtsuka1, M Oyanagi, Y Mafune
1First Department of Biochemistry, Niigata University School of Medicine, Japan.
Abstract:
Distribution of the p53 pseudogene within the house mouse species (genus Mus) was studied with polymerase chain reaction for 37 individuals that were caught at different localities. Pseudogene-specific fragments were detected in some, but not all, individuals of Mus musculus subspecies regardless of locality and type of subspecies. In addition, 3 of 7 individuals belonging to different Mus species carried the pseudogene in their genomes. These results show the existence of an interspecific presence/absence polymorphism of the p53 pseudogene in mice. Sequence analysis of 11 amplified 0.3-kb fragments suggested that the pseudogene originated in an ancestral mouse about 7 million years ago. Thus alleles with and without the p53 pseudogene have persisted through the mice speciation. The evolutionary rate for the p53 functional gene was also estimated to be about 3.3 x 10(-9) per nucleotide site per year.
Insights
The p53 pseudogene is present in some, but not all, mouse species (genus Mus). This interspecific polymorphism suggests the pseudogene has persisted through mouse evolution for millions of years.
Area of Science:
- Genetics and Evolutionary Biology
- Molecular Biology
- Genomics
Background:
- The p53 gene is a critical tumor suppressor.
- Pseudogenes, non-functional gene copies, can provide insights into evolutionary history.
- Understanding gene distribution and evolution in model organisms like mice is crucial.
Purpose of the Study:
- To investigate the distribution of the p53 pseudogene across different species within the genus Mus.
- To determine if the presence or absence of the p53 pseudogene represents a significant polymorphism.
- To estimate the origin and evolutionary persistence of the p53 pseudogene.
Main Methods:
- Polymerase chain reaction (PCR) was used to detect pseudogene-specific fragments.
- DNA samples were analyzed from 37 individuals of the genus Mus, including various Mus musculus subspecies and different Mus species.
- Sequence analysis was performed on amplified pseudogene fragments.
Main Results:
- The p53 pseudogene was detected in some, but not all, individuals of Mus musculus subspecies.
- The pseudogene was also found in 3 out of 7 individuals from different Mus species, indicating interspecific presence/absence polymorphism.
- Sequence analysis suggested the pseudogene originated approximately 7 million years ago.
Conclusions:
- The p53 pseudogene exhibits an interspecific presence/absence polymorphism in mice.
- Alleles with and without the p53 pseudogene have persisted throughout mouse speciation.
- The evolutionary rate of the functional p53 gene was estimated at 3.3 x 10^-9 per nucleotide site per year.