This web page was produced as an assignment for Genetics 564, an undergraduate course at UW-Madison .
What is gene homology?
Gene homology describes the degree of similarity of two genes in two different organisms due to common ancestry. Genes are classified as homologous if they are highly similar to each other.
In addition to providing insights to evolutionary ancestry, gene homology is also useful in helping to understand gene function. It is difficult if not impossible to study certain genes in human subjects due to limitations to how they can be manipulated. But if a gene has a homolog in a model organism like a fruit fly, it can be easily tested. As an example, fruit flies have short life cycles, can produce a lot of progeny, and are easy to manipulate.
Identifying homologs
Gene homologs can be identified using BLAST, a bioinformatics tool that aligns and compares an input sequence (DNA, mRNA or protein) to similar sequences in its database. BLAST can be used to provide information on how conserved a sequence is as compared to that in another organism.
DRD2 gene homologs
Gene homology describes the degree of similarity of two genes in two different organisms due to common ancestry. Genes are classified as homologous if they are highly similar to each other.
In addition to providing insights to evolutionary ancestry, gene homology is also useful in helping to understand gene function. It is difficult if not impossible to study certain genes in human subjects due to limitations to how they can be manipulated. But if a gene has a homolog in a model organism like a fruit fly, it can be easily tested. As an example, fruit flies have short life cycles, can produce a lot of progeny, and are easy to manipulate.
Identifying homologs
Gene homologs can be identified using BLAST, a bioinformatics tool that aligns and compares an input sequence (DNA, mRNA or protein) to similar sequences in its database. BLAST can be used to provide information on how conserved a sequence is as compared to that in another organism.
DRD2 gene homologs
Organism | mRNA Name | Accession Number | GI Number | mRNA Sequence | % Identical | |
Human (Homo sapiens) | Human dopamine D2 receptor (DRD2) mRNA, complete cds | M29066.1 | 181828 | FASTA | ||
Chimpanzee (Pan troglodytes) | PREDICTED: Pan troglodytes dopamine receptor D2 (DRD2), transcript variant X1, mRNA | XM_009424046.1 | 694946768 | FASTA | 99% | |
Orang Utan (Pongo abelii) | PREDICTED: Pongo abelii dopamine receptor D2 (DRD2), transcript variant X1, mRNA | XM_009247074.1 | 686738620 | FASTA | 98% | |
Rhesus Macaque (Macaca mulatta) | PREDICTED: Macaca mulatta dopamine receptor D2, transcript variant 3 (DRD2), mRNA | XM_001085571.2 | 297269209 | FASTA | 97% | Horse (Equus caballus) | PREDICTED: Equus caballus dopamine receptor D2 (DRD2), transcript variant X3, mRNA | XM_005611574.1 | 545221209 | FASTA | 92% |
House Mouse (Mus musculus) | Mus musculus dopamine receptor D2 (Drd2), mRNA | NM_010077.2 | 148747211 | FASTA | 90% | Rabbit ( Oryctolagus cuniculus) | PREDICTED: Oryctolagus cuniculus dopamine receptor D2 (DRD2), transcript variant X2, mRNA | XM_008261225.1 | 655601558 | FASTA | 90% |
Pig( Sus scrofa) | Sus scrofa dopamine receptor D2 (DRD2), mRNA | NM_001244253.1 | 346716327 | FASTA | 88% | |
Chicken(Gallus gallus) | Gallus gallus dopamine receptor D2 (DRD2), mRNA | NM_001113290.1 | 164518969 | FASTA | 80% | Blind cave fish (Astyanax mexicanus) | PREDICTED: Astyanax mexicanus D(2)-like dopamine receptor-like (LOC103035621), transcript variant X2, mRNA | XM_007245241.1 | 597762681 | FASTA | 79% |
Discussion
The DRD2 gene was found to be fairly well conserved in vertebrates, but not in invertebrates.