Varia

Varia predicts and analyzes variable gene sequences and their encoded protein domain compositions from short sequence tags to support studies of gene diversity and expression in pathogens such as Plasmodium falciparum.

Key Features:

• Prediction from short sequence tags: Uses short sequence tags (150-200 base pairs) to predict likely gene sequences and encoded protein domain composition.
• Domain composition analysis: Leverages unique sequence tag similarities within a gene family to infer domain architectures of queried genes.
• Extended annotated var genome database: Compares query tags to an extended annotated var genome database to identify genes with identical tag sequences and determine probable domain composition.
• Putative gene sequence reconstruction: Returns putative gene sequences and domain compositions from partial sequences.
• Expression profiling from NGS tags: Compiles overall domain prevalence among var transcripts identified and quantified through next-generation sequencing of varDBLα-sequence tags in complex samples, including patient-derived data.
• Two-module system: Implements Varia VIP (Variable Gene Identification Pipeline) for sequence prediction and Varia GEM (Gene Expression Module) for expression profiling.

Scientific Applications:

• Plasmodium falciparum var gene analysis: Enables prediction and characterization of var gene domain repertoires, including PfEMP1-encoding sequences.
• Immune evasion and host interaction studies: Supports investigation of genetic diversity underlying immune escape mechanisms and host–pathogen interaction phenotypes.
• Expression profiling in clinical samples: Facilitates rapid profiling of variable gene expression patterns in complex and patient-derived samples.
• Functional inference and validation: Provides inferred domain compositions from partial tags to guide experimental validation of gene function.

Methodology:

Predicts gene sequences and domain compositions by matching short sequence tags (150–200 bp) against an extended annotated var genome database using sequence tag similarity, returns putative gene sequences and domain architectures, and quantifies domain prevalence from next-generation sequencing of varDBLα-sequence tags via two modules: Varia VIP (identification/prediction) and Varia GEM (expression profiling).