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Purebreeding guinea pigs with rough textured black coats were crossed to purebreeding guinea pigs with smooth textured white coats - VCE - SSCE Biology - Question 2 - 2003 - Paper 1
Question 2
Purebreeding guinea pigs with rough textured black coats were crossed to purebreeding guinea pigs with smooth textured white coats. The F1s were all rough textured w... show full transcript
Worked Solution & Example Answer:Purebreeding guinea pigs with rough textured black coats were crossed to purebreeding guinea pigs with smooth textured white coats - VCE - SSCE Biology - Question 2 - 2003 - Paper 1
Step 1
What information provided in the results confirms that there are two genes each with two alleles?
Answer
The presence of four phenotypes in the F2 generation indicates that at least two genes are involved. Each gene has two alleles, with one gene determining coat color and another determining coat texture. The phenotypic ratio observed is indicative of the dihybrid inheritance pattern, supporting the existence of two separate genes controlling these traits.
Step 2
Step 3
Step 4
Step 5
What does 'assort independently' mean?
Answer
'Assort independently' means that the distribution of alleles for different genes occurs independently of each other during gamete formation. In this context, the alleles for the texture locus and the color locus segregate into gametes without influencing each other's chances of being included. Therefore, an R or r allele can combine with a B or b allele in any combination.
Diagram:
R r B b
-------------
B| RB | Rb |
b| rB | rb |
This Punnett square illustrates how the genotypes can assort independently in the gametes.