单选题一般说，X连锁隐性突变比常染色体隐性突变较易研究。下面三个原因中哪个正确：______。 A.X连锁隐性基因位于X染色体上，容易检测 B.X连锁隐性基因纯合率高 C.X连锁隐性基因容易在雄性半合子身上表现出来 D.以上都不对

单选题人类白化病是常染色体单基因隐性遗传病，这意味着白化病患者的双亲必须是(假定白化症患者不是由新突变引起的)______

单选题转导过程中产生的转导子，下面哪种说法对转导子的描述是正确的? ____

单选题As thick-skinned elected officials go, FIFA President Joseph S. Blatter is right up there with Bill Clinton. The chief of the Zurich-based group that oversees World Cup soccer hasn't been accused of groping any interns, but that's about all he hasn't been accused of. Vote buying, mismanagement, cronyism--and that's just for starters. Yet the 66-year-old Swiss shows no sign of abandoning his campaign for a second four-year term. Blatter, a geek of dispensing FIFA'S hundreds of million in annual revenue to inspire loyalty, even stands a good chance of reelection. At least he did. Since mid-March, he has seen a credible challenger emerge in Issa Hayatou, president of the African Football Confederation. Hayatou, a 55-year-old from Cameroon, leads a group of FIFA reformers that also includes FIFA Vice-President Lennart Johansson, a Swede who lost the presidential election to Blatter in 1998. These contenders' mission: to end what they call the culture of secrecy and lack of accountability that threatens FIFA with financial disaster. Representatives of the world's 204 national soccer associations meet in Seoul on May 29, and the rebels are given a chance of unseating Blatter. But even they concede that the FIFA honcho won't be easy to dislodge. Blatter's staying power seems incredible, given the array of misdeeds attributed to him and his circle. However, there are signs that FIFA'S troubles are bigger than Blatter is saying. The insurgents have already won one victory: They persuaded the rest of the executive board to order an audit of FIFA finances. But Blatter--who claims, through a spokesman, that the accusations are a smear campaign-should not be underestimated. At least publicly, sponsors and member associations remain remarkably siient with the controversy. For example, there is no outward sign of outrage from German sports equipment maker Adidas Salomon, which is spending much of its $ 625 million marketing budget on the World Cup. "We don't expect current developments within FIFA to have a negative impact on our expectations" for the World Cup, says Michael Riehl, Adidas head of global sports marketing. The conventional wisdom is that fans don't care about FIFA politics. Says Bernd Schiphorst, president of Hertha BSC Berlin, a top-ranked German team: "I've no fear that all these discussions are going to touch the event." Still, the Olympic bribery scandals and the doping affair in the Tour de France show that sleazy dealings can stain the most venerable athletic spectacle. "For the Good of the Game" is FIFA'S official motto. The next few months should show whether it rings true.

单选题下列有关细菌遗传学的叙述哪句正确?______ A.细菌染色体大多都是环状染色体 B.Hfr×F-杂交时，几乎所有的F-菌株都变成了Hfr菌株 C.细菌内含有许多附加因子，他们并不与环状染色体结合，这种因子称附加体 D.上述答案都对

单选题一个红花非整倍体与隐性白花双体杂交，F1全为红花个体，且所有植株均有无效花粉。用其中一株与aa双体测交，后代呈1:1显隐性分离。红花非整倍体的基因型为______。 A．AAAA B．AAAa C．AAaa D．Aaaa

单选题分子进化理论可以通过DNA的序列比较推算物种或分子的进化速度和机制，这种理论假设( )。

单选题一个婴儿表现女性特征，她的口腔上皮黏膜细胞中有一个巴氏小体，这个婴儿是：______。 A．Klinfelter综合征 B．Turner综合征 C．Down综合征 D．XXX个体 E．正常的

单选题隔离导致( )。

单选题一对等位基因，在杂合的情况下，两种基因的作用都可以完全表现出来，这叫做( )。

单选题从染色质到染色体的四级结构模型中，核小体与核小体的连接上结合着一个组蛋白分子，这个组蛋白分子是______。 A.H2A B.H1 C.H3 D.H2B

单选题下列各条中的哪一条不属于达尔文进化论的一部分?( )