A tiger mouse and relatives. Variants caused by an activated transposable element?

Area of Science:

• Genetics and Genomics
• Developmental Biology
• Mammalian Genetics

Background:

• Laboratory mice are crucial models for genetic research.
• The Peruvian mouse genome is known for high mutation rates and aberrant karyotypes.
• The yellow (AyA) coat color gene in mice is associated with ecotropic murine leukemia virus.

Purpose of the Study:

• To investigate the genetic basis of an unusual 'Tiger' mouse phenotype.
• To explore the influence of the Peruvian genome on genetic stability and mutation.
• To examine the inheritance patterns and potential mosaicism in the affected mouse.

Main Methods:

• Phenotypic analysis of a novel 'Tiger' mouse and its progeny (F1, F2, F3 generations).
• Genetic crosses with laboratory stock mice and allozyme typing.
• Karyotype analysis to assess chromosomal normality.
• Investigation of unusual genetic events in related mice, including mutations and translocations.

Main Results:

• A unique 'Tiger' mouse (yellow with black dorsal stripes) appeared from a cross involving a Peruvian-influenced mother.
• The 'Tiger' mouse exhibited gonosomic mosaicism (Ayat/atat), with the homozygous cell line likely arising from the heterozygous one.
• Allozyme segregation was normal except for the Es-3 locus, where the 'Tiger' mouse was homozygous.
• Related mice showed increased mutations, probable translocations, and somatic defects, all tracing back to the Peruvian-influenced mother.

Conclusions:

• The Peruvian genome component in the mother likely induced DNA sequence instability, affecting the yellow gene and causing widespread genetic disturbances.
• This instability may be linked to the high mutation and aberrant karyotype occurrence in the Peruvian genome.
• The findings suggest a complex interplay between specific genomic backgrounds, DNA instability, and the manifestation of mutations and developmental defects.