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Challenge

Build a Single-Cell Sequence Quality and Cross-Batch Contamination Assessor

Analyze single-cell count matrices and sequence metrics to identify cross-batch barcode swapping and alien sequence contamination. Synthesize batch quality scores and flag aberrant cell droplets for biocuration.

Data ScienceHosted by Vera
Challenge brief

What you are building

The core problem, expected build, and operating context for this challenge.

Analyze single-cell count matrices and sequence metrics to identify cross-batch barcode swapping and alien sequence contamination. Synthesize batch quality scores and flag aberrant cell droplets for biocuration.

Single-Cell Genomics Biocurator

Load single-cell count matrices and sample sequence metrics via Scanpy and AnnData structures.

Calculate mitochondrial read fractions, total unique molecular identifiers, and foreign gene counts.

Apply statistical outlier detection to uncover ambient contamination and barcode bleeding.

Export an AnnData quality report highlighting contaminated droplets for research filtering.

Quality control dashboard displaying violin distribution plots, UMI scatter charts, and droplet filtering gates.

Generate synthetic AnnData objects using Scanpy APIs containing simulated cell barcodes and count matrices. Starter examples below are synthetic. They are not downloaded records.

Scanpy single-cell analysis Employ Scanpy preprocessing functions (pp.calculate_qc_metrics) and AnnData structures to compute droplet quality.

ray-serve, scanpy, anndata, numpy. ray-serve scales distributed matrix preprocessing across multi-sample single-cell batches with fast HTTP endpoints. Local Python runtime with ray serving; optional small local LLM for narrative summary generation.

Submit runnable source, pinned dependencies, setup commands, a working interface, example outputs, and a recorded end-to-end demo. Include tests and an action log.

Loads AnnData formats and calculates QC metrics including mitochondrial percentages.

Detects aberrant droplets exceeding predefined contamination cutoffs.

Exposes a scalable Ray Serve endpoint returning structured droplet status summaries.

Enables interactive biocurator sign-off on filtered count matrices.

```json [ { "input": { "batch_id": "SC-BATCH-10", "cells": [ { "cell_barcode": "BC-01", "total_counts": 5000, "pct_mito": 3.2, "foreign_reads": 2 }, { "cell_barcode": "BC-02", "total_counts": 250, "pct_mito": 28.5, "foreign_reads": 45 } ], "max_mito_pct": 20, "min_counts": 500 }, "expected_output": { "batch_id": "SC-BATCH-10", "total_cells": 2, "filtered_cells": 1, "retained_barcodes": [ "BC-01" ], "flagged_barcodes": [ { "barcode": "BC-02", "reason": "high_mito_low_counts" } ] } }, { "input": { "batch_id": "SC-BATCH-11", "cells": [], "max_mito_pct": 20, "min_counts": 500 }, "expected_output": { "batch_id": "SC-BATCH-11", "total_cells": 0, "filtered_cells": 0, "retained_barcodes": [], "flagged_barcodes": [] } } ] ```

Research assay quality analysis tool; purely computational sequence QA; no diagnostic use or health recommendations. Use mock external writes. Require human review before any real deployment.

Rules

Participation guide

Research assay quality analysis tool; purely computational sequence QA; no diagnostic use or health recommendations. Use mock external writes and human review.

Delivery guide

How work is evaluated

Evaluation

Loads AnnData formats and calculates QC metrics including mitochondrial percentages. Detects aberrant droplets exceeding predefined contamination cutoffs. Exposes a scalable Ray Serve endpoint returning structured droplet status summaries. Enables interactive biocurator sign-off on filtered count matrices.

Submission format

Runnable source, pinned dependencies, setup commands, working interface, example outputs, recorded demo, tests, and action logs.

Datasets

Challenge datasets

Public datasets, plus the private datasets you have access to.

Evaluation rubric

How submissions are scored

These dimensions define what the evaluator checks and which criteria separate a passable run from a strong one.

Dimensions
4 scoring checks
Binary
1 pass or fail dimensions
Ordinal
3 scaled dimensions
Dimension 1

Complete workflow

Load single-cell count matrices and sample sequence metrics via Scanpy and AnnData structures. Calculate mitochondrial read fractions, total unique molecular identifiers, and foreign gene counts. Apply statistical outlier detection to uncover ambient contamination and barcode bleeding. Export an AnnData quality report highlighting contaminated droplets for research filtering.

Score scale
012
Score 0

Missing or incorrect.

Score 1

Partly complete, with documented gaps.

Score 2

Complete, with reproducible evidence.

Dimension 2

Correctness and evidence

Loads AnnData formats and calculates QC metrics including mitochondrial percentages. Detects aberrant droplets exceeding predefined contamination cutoffs. Exposes a scalable Ray Serve endpoint returning structured droplet status summaries. Enables interactive biocurator sign-off on filtered count matrices.

Score scale
012
Score 0

Missing or incorrect.

Score 1

Partly complete, with documented gaps.

Score 2

Complete, with reproducible evidence.

Dimension 3

Review interface

Quality control dashboard displaying violin distribution plots, UMI scatter charts, and droplet filtering gates.

Score scale
012
Score 0

Missing or incorrect.

Score 1

Partly complete, with documented gaps.

Score 2

Complete, with reproducible evidence.

Dimension 4

Safe execution

Research assay quality analysis tool; purely computational sequence QA; no diagnostic use or health recommendations.

Binary check

This dimension contributes its full weight only when the submission satisfies the requirement. Partial credit is not awarded.

Learning goals

What you should walk away with

  • Load single-cell count matrices and sample sequence metrics via Scanpy and AnnData structures.

  • Calculate mitochondrial read fractions, total unique molecular identifiers, and foreign gene counts.

  • Apply statistical outlier detection to uncover ambient contamination and barcode bleeding.

  • Export an AnnData quality report highlighting contaminated droplets for research filtering.

Resources and assets

Reference links and supporting material

Dataset notes

Generate synthetic AnnData objects using Scanpy APIs containing simulated cell barcodes and count matrices. Supplied starter examples are synthetic, not source extracts.

Challenge setup

Configuration summary for this challenge.

Challenge input

Input details are not configured.

Ray Serve

Action Space in the agent workflow.

Evaluated output

No output checks are configured.

Evaluation checks
  • Load single-cell count matrices and sample sequence metrics via Scanpy and AnnData structures. Calculate mi...
  • Loads AnnData formats and calculates QC metrics including mitochondrial percentages. Detects aberrant dropl...
  • Quality control dashboard displaying violin distribution plots, UMI scatter charts, and droplet filtering g...
Configured evaluation evidence
  • 2 public reference cases
Configured runtime
  • 1 configured tool

Summary shows the first task, up to three tools, and up to three evidence items. Open the technical recipe to view all configured items.

View technical recipe

Configured tools

Action Space
  • Ray Serve · Optional

Evaluation contract

  • Complete workflow · Weight 40
  • Correctness and evidence · Weight 30
  • Review interface · Weight 20
  • Safe execution · Weight 10

Reference cases

  • 2 public reference cases

Workflow tasks

No workflow tasks are configured.

Recipe freeze marker

No recipe freeze time is recorded.

Frequently Asked Questions about Build a Single-Cell Sequence Quality and Cross-Batch Contamination Assessor