Related Experiment Video
Updated: Jun 29, 2026
12:00
A Practical Guide to Phylogenetics for Nonexperts
Published on: February 5, 2014
GenBlastA: enabling BLAST to identify homologous gene sequences
Rong She1, Jeffrey S-C Chu, Ke Wang
1School of Computing Science, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 Canada.
Genome Research
|October 8, 2008
Summary
The genBlastA algorithm effectively filters BLAST results, identifying homologous gene sequences by grouping high-scoring pairs (HSPs). This tool simplifies complex genomic data, improving the accuracy of finding candidate genes.
Area of Science:
- Bioinformatics
- Computational Biology
- Genomics
Background:
- BLAST (Basic Local Alignment Search Tool) is widely used for sequence similarity searches.
- BLAST results often contain numerous irrelevant fragments (noises) alongside significant homologous sequence hits (signals).
- Extracting full-length candidate homologous genes from raw BLAST reports is challenging for researchers.
Purpose of the Study:
- To develop an automated method for filtering and grouping significant homologous sequence hits from BLAST outputs.
- To improve the efficiency and accuracy of identifying candidate genes within large genomic datasets.
Main Methods:
- A novel graph-based algorithm, genBlastA, was designed.
- The algorithm utilizes a unique edge length metric based on biological criteria.
- Shortest paths in the graph represent filtered groups of HSPs corresponding to candidate genes.
Main Results:
- genBlastA successfully filters high-scoring pairs (HSPs) into distinct groups, each representing a candidate homologous gene.
- The algorithm demonstrates high efficiency and accuracy in identifying homologous sequences.
- genBlastA outperforms existing methods for similar tasks.
Conclusions:
- genBlastA provides an effective solution for the overwhelming nature of raw BLAST results.
- The graph-based approach with a novel edge metric accurately identifies homologous genes.
- This tool enhances the usability of BLAST for genomic research.
Related Concept Videos
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
02:05Gene Evolution - Fast or Slow?
The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...
In contrast, regions which code...
01:57Gene Families
Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
02:57Southern Blot
Agarose gel electrophoresis is very useful in separating DNA fragments by size. Running a DNA ladder containing fragments of the known length alongside the sample helps determine the approximate length of the sample DNA fragments. However, additional steps are needed to verify the sequence identity of the sample DNA fragments.
Denatured DNA fragments must be transferred onto a carrier membrane from the gel to make it accessible to a probe - a small ssDNA fragment complementary to the target DNA...
Denatured DNA fragments must be transferred onto a carrier membrane from the gel to make it accessible to a probe - a small ssDNA fragment complementary to the target DNA...
03:36Genome Annotation and Assembly
The genome refers to all of the genetic material in an organism. It can range from a few million base pairs in microbial cells to several billion base pairs in many eukaryotic organisms. Genome assembly refers to the process of taking the DNA sequencing data and putting it all back together in a correct order to create a close representation of the original genome. This is followed by the identification of functional elements on the newly assembled genome, a process called genome annotation.