Reverse Progeny Mapping for Epistatic Loci Detection

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Solution Overview

Problem

Current methods for mapping complex traits in plants, such as yield and stress tolerance, face challenges in identifying loci that interact epistatically, as traditional QTL mapping assumes additivity between loci, leading to difficulties in measuring non-additive contributions and interactions, especially in heterozygous states.

Innovation Solution

The method, called Reverse Progeny Mapping (RPM), utilizes gametes from abnormal meiotic divisions, specifically Second Division Restitution (SDR) spores, which are diploid, allowing for the identification of heterozygous loci that segregate in the next generation, enabling the mapping of traits dependent on polygenic loci and epistatic interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional QTL mapping methods are used to map complex traits, then the analysis assumes additivity between loci, but this leads to difficulties in measuring non-additive contributions and epistatic interactions

Engineering Contradiction:

Improveease of trait mappingVSAvoidprecision of locus interaction detection

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent inverts the traditional QTL mapping approach by using reverse progeny mapping. Instead of analyzing the phenotype of offspring to map loci (forward mapping), the method analyzes the genotype of parents to predict and map loci based on their segregating alleles in the progeny. This inversion enables the detection of epistatic interactions by examining the genetic constitution of parents rather than relying on additive phenotype analysis of offspring.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent segments the complex trait analysis into separate components by examining individual loci and their interactions independently. Through reverse progeny mapping, each locus can be analyzed for its contribution to the trait while controlling for other loci, allowing the segmentation of epistatic effects from additive effects. This enables precise measurement of non-additive contributions by isolating specific locus interactions.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If conventional mapping methods are used, then the genetic architecture is simplified to additive effects, but this fails to capture the complexity of polygenic loci and interdependent interactions

Engineering Contradiction:

Improvesimplicity of genetic modelVSAvoidaccuracy of trait prediction

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the parameter of analysis from phenotypic expression (which reflects additive effects) to genotypic constitution (which reveals epistatic interactions). By using reverse progeny mapping to analyze the genetic makeup of parents and their segregating alleles, the method captures the full complexity of polygenic loci and interdependent interactions while maintaining a manageable analytical framework.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If molecular markers are used to indicate trait presence, then the trait can be detected early, but the method cannot distinguish between different genetic constitutions that produce the same phenotype

Engineering Contradiction:

Improvetime for trait detectionVSAvoidinformation about genetic constitution

Core Design Contradiction:

Loss of timeVSLoss of information

Solution Approach 1:

The patent uses reverse progeny mapping as an intermediary method that bridges the gap between early trait detection and genetic constitution analysis. By analyzing the genotypic data from parents and their segregating alleles in the progeny, the method provides information about the underlying genetic architecture without requiring extensive phenotypic analysis, thus maintaining both early detection capability and genetic information.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7860658B2Reverse progeny mapping

Publication Date: 2010.12.28 RIJK ZWAAN ZAADTEELT & ZAADHANDEL BV

AI summary

Provided is a method for mapping traits in organisms, in particular in plants. The method comprises a) providing a population of SDR-0 organisms, in particular plants, that each arise from one member of a population of unreduced cells resulting from second division restitution, in particular a population of unreduced spores; b) producing SDR-1 progeny populations of each of these SDR-0 organisms; c) phenotyping the SDR-1 progeny populations to identify segregating traits within each SDR-1 progeny population; d) if segregating progeny are present in a SDR-1 progeny population, genotyping the corresponding SDR-0 organism and comparing the genotype thereof with the genotype of the other SDR-0 organisms to identify heterozygous chromosomal regions associated with the occurrence of the segregating trait identified in the SDR-1 progeny population.