Brassica Genotyping Array Services: Scalable 40K Solutions for Genomic Selection

Leafy Brassica crops possess a complex genomic architecture characterized by an ancestral whole-genome triplication (WGT) event. This evolutionary history has resulted in extensive subgenomic redundancy, where multiple highly similar sequences (paralogs) exist for a single functional gene. CD Genomics provides specialized Brassica Genotyping Array Services utilizing advanced Liquid-phase Targeted Sequencing (GBTS) to deliver high-fidelity, diploid-like SNP calling by effectively filtering out off-target homologous sequences. Breeders can now access clean genetic data even within the most challenging regions of the genome.

Service Highlights

Standardized 40K Core Panel with 40,000 markers Advanced Paralog Filtering for triplicated genomes Targeted functional loci for Resistance & Quality Analysis-ready VCF/HapMap delivery for MAS & GWAS

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Solving Subgenomic Complexity in Triplicated Brassica Genomes

Leafy Brassica crops possess a complex genomic architecture characterized by an ancestral whole-genome triplication (WGT) event. Traditional genotyping methods, such as solid-phase SNP microarrays, often struggle with paralogous gene interference, leading to noisy signals and ambiguous genotype calls in these multi-copy regions.

Our Brassica 40K service utilizes advanced Liquid-phase Targeted Sequencing (Genotyping by Targeted Sequencing, GBTS) to physically isolate specific target loci before sequencing. By employing highly specific molecular hybridization probes in solution, we achieve superior capture efficiency, effectively filtering out off-target homologous sequences from the genetic background. This approach ensures high-fidelity, diploid-like SNP calling by ensuring that sequences are mapped back to their unique subgenomic positions, allowing breeders to access high-resolution data.

How CD Genomics delivers this service

What it is: Scalable 40K SNP genotyping for Brassica vegetables.
What we do: Targeted capture, paralogous filtering, and variant calling.
What you get: Analysis-ready VCF/HapMap datasets with trait-linkage insights.

Technical Specs: The Brassica 40K Core Panel

Our standardized 40K panel balances marker density with functional relevance to support high-resolution trait mapping and population genetics.

Feature	Technical Specification	Research Application
Optimized Density	40,000 meticulously selected markers	Comprehensive genome coverage.
Functional Enrichment	Exonic, promoter, and regulatory regions	High trait linkage discovery.
Architecture	Liquid-phase GBTS platform	Custom supplementation for proprietary lines.
Data Format	VCF / HapMap standardized outputs	Immediate ingestion into GWAS and GS software.

The liquid-phase format ensures deep coverage of target loci, providing a more consistent dataset compared to traditional GBS approaches while remaining adaptable as new resistance genes or metabolic pathways are discovered.

Breeding Applications: From Disease Resilience to Quality Traits

Clubroot Resistance (CR)

Rapidly screen for loci associated with Plasmodiophora brassicae resistance, a critical priority for developing durable, resistant cultivars.

Bolting Tolerance

Identify specific markers linked to flowering time to extend the harvest window and ensure marketability across different seasons.

Morphological Selection

Map the genetic architecture of leaf shape, petiole color, and plant architecture to meet evolving consumer preferences.

Metabolic Profiling

Target functional markers for glucosinolates and secondary metabolites to enhance the nutritional profile of Brassica vegetables.

Implement early-stage selection at the seedling stage (MAS), drastically reducing the land use, labor, and time required for traditional phenotypic evaluation cycles. Utilise high-density 40K markers to define core haplotypes for yield-related traits.

Structured Workflow and Quality Control

⚡ Your project follows a clear end-to-end workflow designed for the complexities of polyploid-derived genomes.

Workflow for Brassica 40K genotyping including sample prep, capture, and paralog filtering QC gates.

Sample Preparation: Secure logging and barcoding of seeds or tissue using standardized ID mapping protocols.
Specialized DNA Extraction: Utilization of proprietary buffers optimized for Brassica tissues to remove inhibiting polysaccharides and polyphenols.
Target Capture: Precision liquid-phase probe hybridization is performed to isolate the 40,000 target SNP regions from the genomic background.
NGS Genotyping: Next-Generation Sequencing (NGS) is conducted to provide deep coverage of the enriched loci.
QC Gate: Paralogous Filtering: Advanced algorithms filter reads to ensure only single-locus, diploid-like variants are progressed into the final dataset.
Final Deliverables: Delivery of organized SNP matrices, detailed marker annotations, and comprehensive QC reports ready for downstream modelling.

Actionable Bioinformatics for Breeding Insights

Add optional bioinformatics support to turn genotypes into analysis-ready context for your study—especially helpful for cohort screening and multi-batch projects.

Diploid-like SNP Matrices: Distinction between subgenomic copies to provide clean data, reducing false positives in QTL and GWAS analysis.
Population Stratification: PCA-based overviews guide cohort grouping and ancestry review for large-scale studies.
Software Compatibility: Genotypes formatted for immediate use in pipelines including rrBLUP, TASSEL, and GAPIT.
Linkage Disequilibrium (LD) Analysis: Optional support for calculating LD decay and defining haplotype blocks based on 40K data.

Bioinformatics outputs (if selected): Analysis-ready SNP matrix, population insight reports, and kinship checks.

Demo Results: Visualizing Data Resolution

1. Uniform probe density across all 10 chromosomes

2. Cluster plots demonstrating clear diploid-like separation

3. GWAS association profile for QTL discovery

Case Study: Characterization of the BrapaCapture40K Liquid Chip

Citation

Horticulture Research (2025). Developing BrapaCapture40K liquid chip for genetic research and breeding in Brassica rapa.

Background: Brassica breeders require high-density, cost-effective genotyping tools that can overcome the challenges of subgenomic complexity and triplication.

Methods: Researchers developed the BrapaCapture40K liquid chip and validated it using a panel of 384 accessions to evaluate sequencing performance, consistency, and GWAS utility.

Results: The study demonstrated robust performance, including (A) uniform probe density, (C) high MAF and low heterozygosity, and (F, I) clear differentiation of accessions via PCA. The panel successfully identified the BrMYB2 locus associated with coloration traits through GWAS (J), showcasing its precision in trait mapping.

BrapaCapture40K Characterization Figure 1 showing GWAS and PCA results. Characterization of BrapaCapture40K: Figure 1 illustrates uniform probe density (A), low missing rates (C), PCA-based differentiation (F, I), and GWAS precision for coloration traits (J).

Conclusion: BrapaCapture40K is a flexible and powerful tool for precision breeding, capable of delivering high-resolution insights while overcoming subgenomic complexity.

Submission Requirements

High-quality genomic DNA is essential for optimal hybridization efficiency and high call rates in targeted capture services.

Item	Minimum Requirements	Shipping & Prep Notes
Purified gDNA	Conc. ≥ 20 ng/μL; Total ≥ 1.0 μg	A260/280: 1.8-2.0. Must be RNase treated and free of polysaccharides.
Seeds	20–50 viable seeds	Ship dry in secure, labeled tubes. Ideal for long-term project stability.
Leaf Tissue	100–200 mg (fresh)	Young leaves preferred; ship on dry ice or lyophilized to preserve DNA integrity.

For unique sample types, challenging preservation conditions, or specific DNA extraction requirements, please contact our scientists for a customized consultation.

FAQ

1) How is subgenome redundancy managed in the 40K panel? ▼

We employ dosage-aware variant calling and stringent single-locus probe filtering to assign variants to their accurate genomic positions, effectively neutralizing paralogous interference.

2) Can the 40K panel be customized for specific breeding programs? ▼

Yes. The liquid-phase format allows for the flexible addition of markers targeting proprietary lines or newly discovered QTLs without the need for a new physical array design.

3) Is this panel suitable for multiple Brassica subspecies? ▼

While optimized for Leafy Brassica crops, the panel targets highly conserved loci, making it effective for multiple related subspecies, including oilseed and turnip varieties.

4) What is the expected marker missing rate for large cohorts? ▼

Due to the high specificity of liquid hybridization, the BrapaCapture40K panel typically maintains a missing rate below 5% for high-quality DNA samples, ensuring dataset integrity.

5) How does the 40K panel compare to traditional WGS? ▼

The 40K panel provides a much more cost-effective solution for large-scale screening while focusing on functional areas, achieving higher effective depth at target sites compared to low-pass WGS.

Get a Quote

Request a consultation for Brassica improvement:

Primary trait focus (Resistance, Bolting, morphology, etc.)
Cohort size and sample type (DNA vs seeds vs tissue)
Research goal: Diversity screening vs Genomic Selection (GS)

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Compliance & Disclaimer: The services described on this page are for Research Use Only (RUO). They are not intended for clinical diagnosis, human treatment, or individual health assessment.

References

Developing BrapaCapture40K liquid chip for genetic research and breeding in Brassica rapa. Horticulture Research (2025). DOI: 10.1093/hr/uhaf123.
Two QTLs controlling Clubroot resistance identified from Bulked Segregant Sequencing. MDPI Genes (2024).

For research purposes only, not intended for clinical diagnosis, treatment, or individual health assessments.

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