本题目来源于试卷: Continuity and Change D.5 Gene Expression，类别为 IB生物学
[单选题]
Which are correct explanations of why the gey8v e7yx v(,jsnome, transcriptome and prot/ iy7 u6l -qfi yc7l78odqbr3peome of monozygotic twins may dp 7 co7i36/ryyflbdqi -78qluiffer?
I. The genome of two monozygotic twins will differ only due to random mutations as each individual grows and develops from a zygote into an adult.
II. The genome, transcriptome and proteome of two monozygotic twins are the same.
III. The transcriptome and proteome of monozygotic twins differ mostly due to environmental facts which affect gene regulation.
A. I, II and III
B. I only
C. I and III only
D. II and III only
参考答案: C
本题详细解析:
Statement I is correct because monozygotic twins are genetically identical immediately after an embryo divides into two embryos. As repeated rounds of cell division and DNA replication occur different mutations accumulate in each twin and so differences in the genome, transcriptome and proteome develop (Statement II). Statement III is correct because environmental factors affect which genes are turned on or off and to what extent each gene is transcribed and translated into polypeptides (Statement II). Therefore Choice C is correct. Choices A and D are incorrect as they include Statement II. Choice B is incorrect as it does not include Statement III.
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