Continuity and Change D.8 Inheritance (id: d3366ba5a)

本题目来源于试卷: Continuity and Change D.8 Inheritance，类别为 IB生物学

[单选题]
In some animals, the agout txl,4s dwb)9ui allele causes individual hairs to haaagvek1 kf (6+mo/cz z4i9j x*:t rrt)ve a banded pattern. The non-agouti allele causes hairs to be a single colour. Individuals who are heterozygous have hairs wvif 4 */ott(r k gmj xz1c)6a:+ke9razith a banded pattern.

Which combination of parent genotypes would allow for production of offspring that do not have the agouti characteristic?

A. One heterozygous parent and one parent who is homozygous for the agouti allele.
B. Two parents who are both heterozygous.
C. One parent who is homozygous for the agouti allele, and one parent who is homozygous for the non-agouti allele.
D. Two parents who are homozygous for the agouti allele.


参考答案:  B


本题详细解析:
The question states that heterozygous individuals have the banded pattern on their hairs, which means that the agouti trait is dominant. Two heterozygous parents will produce offspring with the dominant and recessive characteristics in the ratio of 3:1 (Choice B). The offspring of a heterozygous individual and a homozygous agouti individual will all receive at least one dominant allele, so they would all be agouti (Choice A). The offspring of at least one parent that is homozygous for agouti will all have the agouti characteristic (Choices C and D).

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