#biomed

Sequencing Celebrity Mice: New Study Compares Genetics of 14 Popular Mouse Models

In a new study published on March 9, 2022 in Cell Genomics,  researchers at the University of California San Diego School of Medicine present a genome-wide map comparing the genetic makeup of 14 common strains of laboratory mice.

In the century since the C57BL mouse strain was first generated, it has become the most popular laboratory rodent for biomedical research. It functions as a sort of “default” mouse, and its genetic makeup is commonly used as a “neutral” backdrop for genetic modifications that model human diseases. The specific C57BL/6J strain from The Jackson Laboratory is currently the most commonly used inbred mouse, with a closely-related C57BL/10 strain widely used in fields, such as immunology. Many additional sub-strains have since been derived from both.

Given the prevalence of these mouse strains in biology research, a comprehensive understanding of their genetic similarities and differences is valuable to researchers, but until recently, such a resource did not exist.

A team led by Abraham Palmer, PhD, and Jonathan Sebat, PhD, professors at UC San Diego School of Medicine, has now identified 352,631 single nucleotide polymorphisms (SNPs), 109,096 small insertions and deletions (INDELs), 150,344 short tandem repeats (STRs), 3,425 structural variations (SVs) and 2,826 differentially expressed genes (DEGenes) among the different strains. Most of the SNPs were clustered into 28 short segments in the genome, indicating that these genetic differences are likely due to an early introgression of an unrelated mouse, rather than recent independent mutations.

The authors say these results can now be used to guide both forward genetic approaches (wherein scientists identify a phenotypic difference between mice and look for the genetic variation that caused it) and reverse approaches (wherein scientists first identify a genetic difference and then assess whether it produces a different phenotype). Either way, they urge researchers to be aware of the unique genetic profile of their strain of choice.

— Nicole Mlynaryk, Bigelow Science Communication Fellow