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A plant species may have red or white flowers - HSC - SSCE Biology - Question 16 - 2008 - Paper 1
Question 16
A plant species may have red or white flowers. Two red-flowered plants were crossed. Most of the offspring had red flowers, but some had white flowers. Explain the ... show full transcript
Worked Solution & Example Answer:A plant species may have red or white flowers - HSC - SSCE Biology - Question 16 - 2008 - Paper 1
Step 1
Explain the presence of both red- and white-flowered offspring
Answer
The presence of both red- and white-flowered offspring can be explained by the concept of incomplete dominance or codominance in genetics.
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Genetic Alleles: Each plant has two alleles for flower color, which can be represented as 'R' for red and 'r' for white. In this case, the red-flowered plants may be homozygous (RR) or heterozygous (Rr).
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Crossing of Plants: When two red-flowered plants are crossed, if one or both of them are heterozygous (Rr), the offspring can inherit a combination of alleles.
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Phenotypic Ratios: If both parent plants are heterozygous (Rr), the offspring's genotypes would be 25% RR, 50% Rr, and 25% rr. This results in approximately 75% of the plants showing the red phenotype and 25% showing the white phenotype, accounting for the observed diversity among the offspring.