In a rat population, three different fur colours can be observed - VCE - SSCE Biology - Question 7 - 2016 - Paper 1
Question 7
In a rat population, three different fur colours can be observed. The rats can have grey, black or white fur.
The production of fur colour pigment in these rats is ... show full transcript
Worked Solution & Example Answer:In a rat population, three different fur colours can be observed - VCE - SSCE Biology - Question 7 - 2016 - Paper 1
Step 1
What conclusion can be made about the location of the two genes on the chromosomes of these rats?
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Answer
The two genes are located on separate chromosomes or are far apart on the same chromosome, which allows for independent assortment during gamete formation.
Step 2
What are all the possible genotypes for this rat?
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Answer
A rat with black fur can have the genotypes: GgAA (grey pigment present) or ggAA (no grey pigment), but can also include other combinations where the presence of at least one 'G' results in the black phenotype.
Step 3
What are the possible genotypes and phenotypes of the offspring?
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Answer
When two heterozygous rats (GgAa) are crossed, the possible genotypes of the offspring can be derived from the gametes:
