Homologous Genes
Homologous Genes - Related Videos
02:31
Homologous Recombination
0 Views •
2020
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
04:13
CRISPR Concatemer-Mediated Multiple Gene Knockout: A Technique to Simultaneously Knockout Multiple Genes by Non-Homologous End-Joining Pathway in Mouse Intestinal Cells
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2025
This video describes a gene knockout technique using a CRISPR-concatemer to simultaneously knock out multiple genes in cultured mouse intestinal organoid cells. This method is used to knock out a diseased gene and to elucidate the function of a gene and its paralogues.
14:23
Recombineering Homologous Recombination Constructs in Drosophila
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Cited by 9 •
2013
Homologous recombination techniques greatly advance Drosophila genetics by enabling the creation of molecularly precise mutations. The recent adoption of recombineering allows one to manipulate large pieces of DNA and transform them into Drosophila6. The methods presented here combine these techniques to rapidly generate large homologous recombination vectors.
05:12
All-in-One CRISPR Genome Editing: A Method for Homology Directed Repair-Based Gene Knock-In in Cultured Cells Using CRISPR-Cas9 System
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2025
In this video, we demonstrate all-in-one CRISPR-Cas9 based genome editing in cultured cells where Cas9 and sgRNA are provided as a single plasmid construct to the cells. The CRISPR-Cas9 system and desired gene to be inserted was introduced in cells through electroporation technique to facilitate successful gene editing.
04:14
Generation of Antibiotic-Marked Mutants in Cyanobacteria via Homologous Recombination
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2025
Source: Lea-Smith, D. J., et al. Generation of Marked and Markerless Mutants in Model Cyanobacterial Species. J. Vis. Exp. (2016)The video demonstrates a method for generating antibiotic-marked mutants in cyanobacteria. The protocol begins with culturing cyanobacteria, followed by centrifugation and washing steps that preserve surface pili. A plasmid carrying an antibiotic resistance gene flanked by homologous sequences is then introduced. During incubation, the plasmid is internalized via pili...
FAQs
Orthologs and paralogs should be interpreted differently when comparing genes. Orthologs reflect divergence associated with speciation, so comparisons between species can highlight functions retained across evolutionary lineages. Paralogs result from gene duplication within a genome and provide a basis for examining how related gene copies may acquire different functions. This distinction helps organize evolutionary and functional comparisons.
Sequence comparisons and conserved domains provide complementary clues when identifying homologous genes. Similarity across sequences can reveal related genes, while conserved domains point to regions maintained across evolutionary history. Examining both types of evidence supports classification into orthologs or paralogs and strengthens functional annotation by linking a gene to related biological information.
Gene duplication creates additional gene copies within a genome, allowing comparisons among related sequences. Those copies can remain functionally conserved or change in function over evolutionary time. Studying paralogs therefore helps biologists examine how genomes diversify while retaining related biological capabilities. The comparison is especially useful when investigating why related genes within one organism may contribute differently to development or other biological processes.
A practical analysis begins by comparing the gene sequences under study, then checking whether conserved domains are shared. Researchers use these observations to determine whether related genes are more consistent with orthology or paralogy. The resulting relationships can support functional annotation and guide comparisons across organisms, turning sequence-level evidence into hypotheses about conserved or changed gene function.
Homologous genes help researchers select model organisms for studies of development and disease. If a gene-related relationship points to biology conserved across organisms, a model may offer a relevant system for investigating that process. Comparative genomics then connects observations in the model with related genes elsewhere, supporting interpretation of whether a function is conserved or has changed.
Functional annotation can draw on relationships among genes to propose biological roles for genes that are less well characterized. Comparing homologous genes across organisms or within a genome supplies evolutionary context, while conserved domains provide additional support. These analyses help distinguish functions likely retained through evolution from those that may have changed, improving interpretation of gene data in biology.