EVOLUTION
SOURCES OF VARIATION IN A POPULATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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One sheep donated DNA, another donated an egg cell, and a third carried Dolly in her womb
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The sperm and egg cells of two sheep were combined, and implanted in the womb of a third sheep
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Scientists combined different pieces of DNA from three separate sheep
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Two fertilized egg cells were implanted in the wombs of two sheep, but only one matured properly
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Detailed explanation-1: -Q. Why did it take three sheep to create one clone? One sheep donated DNA, another donated an egg cell, and a third carried Dolly in her womb. The sperm and egg cells of two sheep were combined, and implanted in the womb of a third sheep.
Detailed explanation-2: -Because Dolly’s DNA came from a mammary gland cell, she was named after the country singer Dolly Parton.
Detailed explanation-3: -They took an egg cell from a different sheep and removed the nucleus. 3. They put one udder cell next to the egg cell without a nucleus and joined them using electricity. The egg cell now contained all the udder cell’s DNA.
Detailed explanation-4: -Analysis of Dolly’s DNA when she was one year old showed that the protective caps on the end of her chromosomes (known as telomeres) were shorter than those of a normal sheep of the same age. Telomeres get shorter with age and it is possible that Dolly’s telomeres had not been fully renewed during the cloning process.