Using progenitor strain information to identify quantitative trait nucleotides in outbred mice

Area of Science:

• Genetics
• Genomics
• Molecular Biology

Background:

• Understanding the genetic basis of complex traits is crucial.
• Quantitative trait loci (QTLs) are key targets for genetic dissection.
• Identifying specific causative variants within QTLs remains challenging.

Purpose of the Study:

• To develop a rapid and cost-effective strategy for molecular-level dissection of quantitative trait loci (QTLs).
• To identify specific sequence variants responsible for phenotypic variation.
• To reduce the number of candidate variants for further investigation.

Main Methods:

• Utilized mapping data from crosses involving multiple inbred strains.
• Incorporated sequence variants from progenitor strains within QTL intervals.
• Employed multipoint analysis to estimate genotypes at ungenotyped polymorphisms.
• Assessed consistency between strain distribution patterns and QTL effects to assign probabilities to sequence variants as quantitative trait nucleotides (QTNs).

Main Results:

• Successfully applied the method to a QTL influencing anxiety on mouse chromosome 1.
• Demonstrated the ability to reduce thousands of potential variants to fewer than 20 candidates.
• Showed that the identified QTN is likely located in a conserved region between human and mouse genomes.

Conclusions:

• The developed strategy offers an efficient approach for fine-mapping QTLs at the molecular level.
• This method significantly accelerates the identification of quantitative trait nucleotides (QTNs).
• The approach is applicable to complex traits and conserved genomic regions.