Chromosomal Inversion Detection via Chromatid-Specific Probe Hybridization

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Solution Overview

Problem

Current methods for detecting chromosomal inversions are insensitive, leading to underestimation of their significance in diseases, including cancer, as they cannot reliably identify inversions due to limitations in karyotype analyses and existing chromosome painting techniques.

Innovation Solution

A method using single-stranded probes specific to one chromatid, which are hybridized to generate a sensitive detection system capable of identifying inversions by distinguishing between sister chromatids through unique DNA sequences, allowing for the visualization of inversions as a switch in probe signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard karyotype analysis or whole chromosome painting is used, then the method is simple and widely applicable, but the detection sensitivity for inversions is low and many inversions remain undetected

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmethod complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention segments the chromosome into two separate sister chromatids and applies different probes to each chromatid. This segmentation allows the detection of inversions that would be invisible in whole chromosome painting, as the orientation difference between sister chromatids becomes detectable through differential probe hybridization patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies different probes with specific orientations to different sister chromatids, creating local quality differences that enable inversion detection. The probes are designed to hybridize in specific orientations to specific chromatids, allowing the detection of inversion events through changes in hybridization patterns.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If G-banding or R-banding is used to detect inversions, then no additional reagents are needed, but inversions can only be detected when they produce recognizable changes in banding patterns

Engineering Contradiction:
Improveinversion detection capabilityVSAvoiddetection reliability
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The invention replaces the mechanical/optical banding pattern recognition system with a molecular hybridization-based detection system. Instead of relying on visual inspection of banding patterns, the method uses probe hybridization to specific DNA sequences on sister chromatids, providing more reliable and sensitive inversion detection that does not depend on the size or position of the inversion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If whole-chromosome FISH painting is used, then stable aberrations like translocations can be observed, but the method is limited to detecting breaks, interchanges and numerical aberrations and cannot detect inversions

Engineering Contradiction:
Improveaberration detection accuracyVSAvoiddetection range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention segments the chromosome painting approach by applying probes specifically to individual sister chromatids rather than painting the entire chromosome. This segmentation enables the detection of inversion events by comparing the hybridization patterns between sister chromatids, expanding the detection range beyond what is possible with whole chromosome painting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a new dimension to chromosome analysis by considering the orientation and specific binding of probes to each sister chromatid separately. This dimensional approach, where probes are oriented and bound specifically to one chromatid or the other, enables the detection of inversions through changes in probe-chromatid association patterns.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides a sensitive and accurate method for detecting chromosomal inversions, enhancing the ability to identify previously undetectable genetic rearrangements and improving the understanding of their role in diseases.

Implementation Method 1

hybridizing the probes to the sister chromatids, wherein a probe set has the ability to cover a specified chromatid from end to end

Methodology Applied
Scientific EffectHybridization: Chemical Bonding

Data Source

PatentEP2079850B1Detection of chromosomal inversions
Publication Date: 2016.02.24 COLORADO STATE UNIV RES FOUND
  • EP2079850B1 patent drawingFigure 1A~1B

AI summary

A method and a kit for the identification of chromosomal inversions is described. Chromosomal inversions are difficult to detect unless they are quite large. The improved ability to detect chromosomal inversions is important to a number of medical applications, such as cancer and birth defects, as examples. Reporter species are attached to oligonucleotide strands designed such that they may hybridize to portions of only one of a pair of single-stranded sister chromatids prepared by the CO-FISH procedure, as an example. If an inversion has occurred, these marker probes will be detected on the sister chromatid at the same location as the inversion on the first chromatid.