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From the cross 2 data it can be concluded that A - VCE - SSCE Biology - Question 12 - 2003 - Paper 1
Question 12
From the cross 2 data it can be concluded that A. straight tail is the dominant phenotype. B. the albino coat, straight-tailed offspring are heterozygous. C. the ago... show full transcript
Worked Solution & Example Answer:From the cross 2 data it can be concluded that A - VCE - SSCE Biology - Question 12 - 2003 - Paper 1
Step 1
A. straight tail is the dominant phenotype.
Answer
To determine if the straight tail is the dominant phenotype, we need to analyze the offspring phenotypes resulting from the testcross. If the majority of the offspring display the straight tail phenotype compared to another phenotype (e.g., kinked), we can conclude that the straight tail is dominant.
Step 2
B. the albino coat, straight-tailed offspring are heterozygous.
Answer
To evaluate the genetic makeup of the albino coat, straight-tailed offspring, we can infer their genotypes from the parental genotypes. If they exhibit the straight tail phenotype, but are crossed with a homozygous recessive individual, the resulting phenotypic ratios will help determine if they are heterozygous.
Step 3
C. the agouti coat and kinky-tailed offspring of the testcross of the F1 are heterozygous at both loci.
Answer
For the F1 offspring exhibiting agouti coat and kinky tails, a testcross with a homozygous recessive individual would confirm if they are heterozygous. If both phenotypes appear in the offspring from this testcross, it indicates heterozygosity at both loci.
Step 4
D. when the F1 mice were testcrossed, they were crossed to mice with agouti-coloured coats and straight tails.
Answer
The testcross involves mating the F1 hybrid with homozygous recessive individuals. In this instance, crossing F1 mice to those with agouti coats and straight tails serves to investigate the dominant and recessive traits present in the F1 genotypes.