Variation in Genetic Relatedness Is Determined by the Aggregate Recombination Process

Area of Science:

• Genetics
• Population Genetics
• Bioinformatics

Background:

• Genetic relatedness, the proportion of the genome shared identically by descent, can vary between relatives due to recombination and segregation.
• Previous variance calculations relied on genetic map length and overlooked crossover interference and sex-specific recombination.

Purpose of the Study:

• To calculate the variance of genetic relatedness based on physical genome proportion (bp) for general pedigrees.
• To explore how recombination processes influence genetic relatedness variance.

Main Methods:

• Developed a model to calculate genetic relatedness variance using physical genome size.
• Analyzed the impact of recombination metrics analogous to the proportion of recombining loci on variance.
• Investigated the role of chromosome number, size heterogeneity, crossover distribution, and sex differences in recombination.

Main Results:

• For grandparent-grandoffspring and sibling relationships, variance is a function of the average proportion of recombining loci.
• For general pedigrees, variance depends on analogous metrics reflecting recombination patterns.
• Crossover interference was shown to reduce genetic relatedness variance by increasing the proportion of recombining loci.

Conclusions:

• The physical proportion of the genome shared identically by descent is a more accurate measure for genetic relatedness variance.
• Understanding recombination processes is crucial for accurately estimating genetic relatedness variance.
• The developed methods enable precise statistical inference for selection in F2 hybrid crosses.