MARS is a data brokering initiative designed to facilitate the submission of multi-omics life sciences studies to multiple specialized repositories. Built as a modular system, MARS enables seamless data exchange between data producers and repositories using the standardized ISA-JSON format.

Unlike centralized platforms, MARS functions as a common framework for decentralized data submissions while ensuring consistent interpretation and validation of ISA-JSON metadata across various repositories. This approach preserves important links between multi-omics datasets derived from the same biological source, ensuring mutual understanding and accurate data interpretation.

MARS is comprised of multiple stakeholders: the end-user, the platform that generates the ISA-JSON, target repositories and the data broker. Each represents key roles in the data submission process. Read more about it in our stakeholders page.

We use ISA-JSON to store and interchange metadata between the end-user and the target repositories because:

• Standardization: ISA-JSON follows the ISA structure (Investigation- Study - Assay), ensuring structured metadata descriptions.
• Versatile: It is not bound to any domain and can represent multi-omics experimental metadata.
• Interoperability: Since ISA-JSON follows a standard format, it facilitates interoperability between different software tools and platforms that support the ISA standard.
• Community Adoption: Widely adopted within the life sciences research community for metadata standardization.

ISA-JSON is generated by ISA-JSON producing platforms and serves as the metadata input for the Data Broker platform, as outlined below.

A platform operated by the Data broker should:

• Accept ISA-JSON as input and submit it to target repositories without any loss of information.
• Extend the ISA-JSON with additional information from the repositories, such as accession numbers assigned to submitted objects.
• Handle error reporting efficiently.
• Maintain an active submission process throughout its duration (up to multiple days), including waiting for repository-side validation steps to complete.
• Enable secure credential management.
• Support data transfer via various protocols (e.g., FTP), ensuring checksum verification for data integrity.
• Allow the Data broker to set up a brokering account or enable end-users to create personal accounts.

Examples of Data broker platforms include ARC, Galaxy, and others.

MARS-CLI is a command-line tool (CLI) used by the Data Broker platform to handle the submission of ISA-JSON metadata to multiple repositories. It automates the submission process, updates ISA-JSON with accession numbers based on repository responses, and ensures smooth data integration.

Built as a Python library, MARS-CLI can be integrated into web applications, ARC, Galaxy, and other platforms. The source code and documentation are available in the mars-cli repository.

ISA-JSON API services, also known as adapters, are being developed and deployed by the repositories that are part of the MARS initiative. This includes programmatic submission, the ingestion of ISA-JSON in order to register the metadata objects and the creation of a receipt according to the MARS repository-api standard.

Track the status of each repository here:

├── repository-services
│   ├── isajson-biosamples/
│   │── isajson-ena/
│   ├── repository-api.md
│   └── README.md
│   └── ...
├── test-data
│   └── ...
└── README.md

• repository-services: Code to deploy repository API endpoints that can accept ISAJSON. See README for deployment instructions.
  • repository-api.md: Describing the receipt standard for repository APIs to follow.
• test-data: Test data to be used in a submission.
• README.md: This file

This project was initiated during the ELIXIR Europe BioHackathon 2022 and has since received continued support through subsequent ELIXIR Hackathons and the ELIXIR Data Platform WP2.