What is Gene Homology?
Homology refers to characteristics in different organisms that are similar because they were inherited by a common ancestor [1]. Homologous genes are identified by similarities in DNA or mRNA sequence, as well as determining conserved motifs and domains.
Homologs of Human (Homo sapiens) Glo 1 Gene
Using the Homologene database on the NCBI website, Glo1 genes were identified as homologs of each other in multiple Eukaryota. The results can be seen here. Several homologous genes were then aligned with human glo1 using NCBI Basic Local Alignment Search Tool (BLAST). BLAST determined percent similarity between human glo1 and glo1 in each organism.
The homologs of glo1 contain large regions of non-coding DNA, hence the differences in length. In order to determine the percent matches between nucleotide sequences, mRNA transcripts were aligned in BLAST instead of DNA sequence. This eliminated differences that would be recognized in non-coding regions.
The homologs of glo1 contain large regions of non-coding DNA, hence the differences in length. In order to determine the percent matches between nucleotide sequences, mRNA transcripts were aligned in BLAST instead of DNA sequence. This eliminated differences that would be recognized in non-coding regions.
Results and Analysis
The glo1 mRNA transcript of the chimpanzee, a very close evolutionary relative to humans, has essentially 100% identity, matching 2021 of 2071 base pairs. The mRNA sequences of cattle, dog, brown rat, and even arabidopsis and yeast also match the mRNA of human glo1 at almost 100%. The function of glyoxalase 1 in these organisms must be highly conserved considering the transcript encoding the protein is essentially identical. It is expected to be a highly conserved enzyme considering the essential function of glyoxalase 1 in clearing the byproducts of glycolysis, a universal biological process.
It is mysterious though as to why glo1 appears more identical to humans in arabidopsis and yeast than in the mouse, an organism that is more closely related to humans. The mouse homolog has 94% identity, which is not extreme, but still less than arabidopsis and yeast identity. This may be due to random variety, or that glyoxalase 1 in mice has a slightly different mechanism of action.
It is mysterious though as to why glo1 appears more identical to humans in arabidopsis and yeast than in the mouse, an organism that is more closely related to humans. The mouse homolog has 94% identity, which is not extreme, but still less than arabidopsis and yeast identity. This may be due to random variety, or that glyoxalase 1 in mice has a slightly different mechanism of action.
Homologous Gene References:
Mouse (Mus musculus)
Arabidopsis (Arabidopsis thaliana)Chimpanzee (Pan troglodytes)
Yeast (Saccharomyces cerevisiae) |
Fruit Fly (Drosophila melanogaster )Brown Rat (Rattus norvegicus)Cow (Bos taurus)Dog (Canis lupus familiaris) |
References
[1] "Tree of Life Web Project." Tree of Life Web Project. N.p., n.d. Web. 21 Feb. 2013.
[2] Altschul S.F., Gish W., Miller W., Myers E.W. and Lipman D.J. (1990)
Basic local alignment search tool. J. Mol. Biol. 215: 403-410.
[2] Altschul S.F., Gish W., Miller W., Myers E.W. and Lipman D.J. (1990)
Basic local alignment search tool. J. Mol. Biol. 215: 403-410.
Site created by: Emma Baar
Last updated: 5-14-2013
University of Wisconsin - Madison
Last updated: 5-14-2013
University of Wisconsin - Madison