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Unformatted text preview: musculus - house mouse
– Arabidopsis thaliana - the thale cress plant
• Also Neurospora crassa - bread mold, and Zea mays - corn Example: Zebraﬁsh and human skin color Zebraﬁsh
• small vertebrates
• many progeny
• easy to raise in labs
• golden mutants were discovered in a pet store in Oregon in the 1970’s.
• have lighter cells, but in the same pattern and number. Example: Zebraﬁsh and human skin color • Genetic characterization showed that the golden phenotype was
caused by a recessive mutation.
• Microscopy: fewer, smaller, and less-dense pigment-containing
structures (melanosomes) in the cells of golden ﬁsh.
• These were the same characteristics observed in light-skinned
humans. The power of model organisms • Keith Cheng and colleagues isolated and sequenced the gene
responsible for the golden phenotype • Encodes a protein required for calcium uptake by melanosomes
• Searched the human database for similar genes and identiﬁed
SLC24A5 The power of model organisms...
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