Biology 9700 · AS & A Level · Principles of genetic technology
Principles of genetic technology — practice question
Russian scientists found the fruits of the flowering plant, Silene stenophylla, in the food cache of a ground squirrel burrow within frozen deposits in Siberia. Dating methods indicate that the ground squirrel stored the fruits about $32\,000$ years ago, just before the ground became permanently frozen. Samples of tissue were removed from the fruits and cultured in a nutrient medium. After applying plant hormones to encourage root and shoot formation, $36$ whole plants were obtained. These ‘regenerated’ plants, which appeared identical to each other, flowered and, after cross-pollination, produced seeds that could germinate.
(a)[3]
Explain why cross-pollination leads to greater genetic variation in the offspring than self-pollination.
(b)[4]
The flowers of modern-day S. stenophylla are similar, but not exactly the same, as those of the ‘regenerated’ plants. Outline how DNA sequencing could be used to compare the DNA of modern-day and ‘regenerated’ S. stenophylla.
(c)[2]
Suggest a straightforward experiment, using plants of modern-day and 'regenerated' S. stenophylla, to determine whether, after 32000 years, they are still the same species.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Cross-pollination uses two parents; self-pollination uses one parent” …