Modeling X-linked ancestral origins in multiparental populations

Area of Science:

• Genetics
• Genomics
• Population Genetics

Background:

• Genome mosaicism models in multiparental populations primarily focus on autosomes.
• X chromosomes are underrepresented in current genomic modeling approaches.
• Accurate modeling of X chromosome ancestry is vital for genetic studies.

Purpose of the Study:

• To extend existing models for ancestral origin processes to the X chromosome in mapping populations.
• To develop hidden Markov models for reconstructing ancestry blocks for X-linked quantitative trait locus (X-QTL) mapping.
• To account for joint recombination, sex-specific chromosome asymmetry, and finite population size.

Main Methods:

• Developed a novel model for ancestral origin processes along the X chromosome.
• Incorporated joint recombination patterns and asymmetry between maternal and paternal X chromosomes.
• Derived analytical results for genetic map expansion and recombination breakpoint density in advanced intercross populations.

Main Results:

• The model is applicable to diverse mapping populations like AIL, CC, HS, DO, and DSPR.
• Derived analytic results for map expansion rates in advanced intercross populations with L inbred founders.
• Showed that X chromosome genetic maps expand at two-thirds the rate of autosomes under specific conditions.

Conclusions:

• The developed model provides a framework for analyzing X chromosome ancestry in multiparental populations.
• The findings highlight differences in genetic map expansion between X chromosomes and autosomes.
• This work is essential for improving X-QTL mapping and understanding sex-chromosome evolution in diverse populations.