If variety is the spice of life, then genetic variability among species is king of the spice rack. While there are tens of thousands of protein-coding genes in the human genome, (estimates range from 23,000 to 30,000), there are tens of millions of single nucleotide polymorphisms (SNP) that exponentially influence the diversity of our gene pool. Initiatives such as the International Hap Map Project provide valuable data on common patterns of human genetic variation and are an important resources for scientists studying mechanisms of human health and disease.
On the other hand, there is a plethora of scientific information on health and disease obtained through studies involving the common laboratory mouse. Considering the importance of genetic variety among humans, it is therefore suprising to learn that the majority of mouse strains used in the laboratory have very little genetic variablity from strain to strain. In a recent paper published in Nature Genetics, the authors estimate that standard laboratory mouse strains carry about 12 million SNPs, which is a fraction of the SNP variation likely to be found among wild-caught mice.
In an effort to compare the genomic data among the various lab strains of mice, the team created the Mouse Phylogeny Viewer which allows researchers to compare the differences and similarities between strains and select the ones most likely to provide the basis for experimental results that can be more effectively extrapolated to the diverse human population.
The authors also suggest that increasing genetic diversity among the lab mouse population would greatly aide in the translatability of data obtained in mice to humans. As such, the authors launched the Collaborative Cross project which has interbred five classic inbred mouse strains and three wild-derived strains and has increased the SNP count from 12 million to 45 million among the lab mouse population.
Reference: Yang et al.: Subspecific origin and haplotype diversity in the laboratory mouse. Nature Genetics, advance online publication Sunday, May 29, 2011.
Sources: Jackson Laboratory