Introduction
Model organisms are organisms used by scientists to carry out experiments to better understand biological processes. Studying humans directly can be both expensive and inefficient as it can sometimes be hard to find humans with conditions of interest. Model organisms that include the same process that is of interest in humans can be used to better understand that process in greater numbers and faster. Model organisms are generally cheaper to house and maintain, reproduce faster, and reproduce in greater numbers all of which make them ideal for use in experiments. In genetics, the best model organisms are those with well studied and understood genomes so that mutations in the organism can be linked to specific genes and as long as those specific genes have comparable genes in humans we can better understand human genes.
Homology is a term that indicates characters that continue through evolutionary history [2]. Put a little more simply, homologous is the word we use to describe characteristics shared between species because they were inherited from common ancestors [1]. As species branch away from common ancestors homologous traits can be modified but the origins and the commonalities are still observable. Homologous traits can sometimes just be seen in organisms bodies but in modern biology we can use sequencing of genes and proteins to compare proteins with an origin and functions that are shared between species. Homology between species is part of how we pick a good model organism for study.
Homology is a term that indicates characters that continue through evolutionary history [2]. Put a little more simply, homologous is the word we use to describe characteristics shared between species because they were inherited from common ancestors [1]. As species branch away from common ancestors homologous traits can be modified but the origins and the commonalities are still observable. Homologous traits can sometimes just be seen in organisms bodies but in modern biology we can use sequencing of genes and proteins to compare proteins with an origin and functions that are shared between species. Homology between species is part of how we pick a good model organism for study.
Results
Genes similar to human RAB27A are found in many organisms. By studying mutations in this gene in well understood model organisms we can gain insight on GS in humans and experiment with new treatments. Below are a number of organisms with proteins homologous to the RAB27A protein in humans.
Rat
(Rattus Norvegicus) Accession Code: NP_059013.1
Length: 221aa Nematoad
(Caenorhabditis Elegans) |
Dog
(Canis Lupus Familiaris) Mouse
(Mus Musculus) |
Zeebrafish
(Danio Rerio) Fruit Fly
(Drosophila Melanogaster) |
|
|
|
Conclusions
In mice, mutations in Rab27A result in the ashen phenotype [3]. Ashen mice have a silvery grey coat in contrast to the brown coat in non-mutant individuals. The ease of identifying Rab27A mutant mice using the ashen phenotype makes them a good candidate for use as a model organism. Use of ashen mice in previous studies gives a starting point to build off of rather than having to start from scratch using another model organism.
References
[1]“Homologous Genes.” Homologous Genes, evolution.berkeley.edu/evolibrary/article/1_0_0/eyes_10.
[2]Wagner, Günter P. “The Developmental Genetics of Homology.” Nature Reviews Genetics, vol. 8, no. 6, 2007, pp. 473–479., doi:10.1038/nrg2099.
[3]Wilson, S. M., et al. “A Mutation in Rab27a Causes the Vesicle Transport Defects Observed in Ashen Mice.” Proceedings of the National Academy of Sciences, vol. 97, no. 14, 2000, pp. 7933–7938., doi:10.1073/pnas.140212797.
Images
Rat: Norway-rat.jpg
Dog: Dog-Canis-lupus-familiaris-1.jpg
Zeebrafish: Zebra-Danio-Habitat.jpg
Nematoad: caenorhabditis_elegans_organisme.jpg
Mouse: mouse.jpg
Fruit Fly: male-fruit-fly.jpg
Ashen Mice: EGFP-Rab27a-rescues-the-phenotype-of-ashen-mice-A-Photograph-showing-one-homozygous.png
[1]“Homologous Genes.” Homologous Genes, evolution.berkeley.edu/evolibrary/article/1_0_0/eyes_10.
[2]Wagner, Günter P. “The Developmental Genetics of Homology.” Nature Reviews Genetics, vol. 8, no. 6, 2007, pp. 473–479., doi:10.1038/nrg2099.
[3]Wilson, S. M., et al. “A Mutation in Rab27a Causes the Vesicle Transport Defects Observed in Ashen Mice.” Proceedings of the National Academy of Sciences, vol. 97, no. 14, 2000, pp. 7933–7938., doi:10.1073/pnas.140212797.
Images
Rat: Norway-rat.jpg
Dog: Dog-Canis-lupus-familiaris-1.jpg
Zeebrafish: Zebra-Danio-Habitat.jpg
Nematoad: caenorhabditis_elegans_organisme.jpg
Mouse: mouse.jpg
Fruit Fly: male-fruit-fly.jpg
Ashen Mice: EGFP-Rab27a-rescues-the-phenotype-of-ashen-mice-A-Photograph-showing-one-homozygous.png