We often attribute key characteristics to one of our parents:" He gets his athleticism from his father." " Her quickness to ange

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问题     We often attribute key characteristics to one of our parents:" He gets his athleticism from his father." " Her quickness to anger—that’s all her mother." Whether the genetics are actually pulling the strings in these cases is another story. But a growing body of research has suggested that heredity does apply to mood disorders—including depression, which afflicts more than 2.8 million adolescents in the U.S. alone—and that there is compelling evidence hereditary ties are strong between mothers and daughters.
    Researchers in a new study of 35 healthy families published in The Journal of Neuroscience this week have found that the brain’s corticolimbic system, responsible for the regulation of emotion—and associated with the manifestation of depressive symptoms—is more likely to be passed down from mother to daughter than from mother to son or father to child. This finding, which supports past evidence from animal research and clinical studies on depression, could provide a better understanding of the role genetics play in mood disorders and other conditions, allowing better identification of at-risk groups and preventive measures.
    "Our study’s uniqueness," says lead author Fumiko Hoeft, an associate professor of psychiatry at the University of California, San Francisco," is that we’re the first one to get the whole family and scan both parents and offspring to look at how similar their brain networks are. And we joke about inheriting stubbornness or organization— but we’ve never actually seen that in human brain networks before."
    Hoeft cites Dr. Seuss’ s children’ s book Horton Hatches the Egg—in which an elephant sits on a bird’s egg in lieu of its actual mother and a hybrid elephant-bird ends up hatching—as a cartoonish example of the inspiration for this research. The forces of both nature and nurture are at play. "What’s relevant is that it shows the profound influence of prenatal impact on offspring, which we often forget," Hoeft adds. "Prenatal input is considered in the most severe cases, like alcohol and smoking. But it happens in everyone. A mom being stressed has an impact on her child’s outcome."
    The finding is particularly relevant in light of the recommendations issued today by the U.S. Preventive Services Task Force, which include the screening of pregnant women and new mothers for depression. Although this recommendation is primarily a response to concerns about the role of the "nurture" side of the equation, Hoeft seeks to unravel how biology plays its part as well.
By quoting "He gets his athleticism from his father" (Para. 1 ), the author intends to

选项 A、analyze the main qualifications of an athlete.
B、discuss hereditary ties between mothers and daughters.
C、exemplify the function of genetics in heredity.
D、describe the essential characteristics of depression.

答案B

解析 (1)根据题干关键词定位至第1段。(2)从思想组织的角度看,第1段第1句起到了引子的作用,目的是为了引出中心议题,即“研究表明,遗传在心境障碍中发挥了作用”(第1段:mood disorders),“有力的证据表明,母女之间遗传关系紧密”(第1段:ties are strong)。据此,选项[B]正确。其实,全文讨论的重点也就是这一主题。
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