单选题群体概念的含义是( )。

单选题____ 可以促进非严格配对的两段DNA发生重组。

单选题达尔文生物进化学说的中心内容是( )。

单选题These are hard times for Deutsehe Bank, despite its huge strides in investment banking. Next week its chief executive, Josef Ackerman, goes on trial in Dusseldorf. Careless words by Rolf Breuer, the head of its supervisory board, led to another court ruling last month that may cost Germany' s biggest bank several hundred million euros in damages. Then there is Parmalat. Although no evidence has emerged of complicity in the Italian dairy group' s fraud, Deutsche' s name has become entwined in the affair. In many other respects, however, Deutsche' s reputation has never been higher. In dubbing it " Bank of the Year 2003", International Financing Review, the capital markets' favorite newssheet, purred that Deutsche was a "lean, aggressive, focused universal bank" In the league tables that investment banks watch so keenly, Deutsche excelled last year as lead manager of bonds and convertible bonds and of some racier products, such as repackaged debt securities and high-yield "junk" bonds. In other disciplines it rarely fell below the top ten in the world. However, it is still nowhere near the top in equity offerings and advice on mergers and acquisitions, except in Germany. It still has a problem with costs,which were a fat 82% of income in the third quarter of 2003, thanks mainly to the thick pay packets of its investment bankers and its poor returns from corporate and retail banking. Mr. Ackermann must try to improve the weak spots while spending two clays a week, probably until June, in a courtroom. He and four others face charges of "breach of trust" over the way bonuses were awarded to board meinbers of Mannesmann, a telecoms company. Mr. Aekermann sat on Mannesmann' s supervisory board. There is no suggestion that he gained personally. Nor was there any harmful intent in Mr. Breuer' s remarks in a television interview about the financial health of the Kirch media group shortly before its bankruptcy. But he was careless, and a Munich court found Deutsche (but not Mr. Breuer) liable for damages, to be set in due course, without right of appeal. The bank said this week it has lodged a protest with the federal supreme court in Karlsruhe. Meanwhile, Kirch has filed a suit against Deutsche in America. Deutsche's involvement with Parmalat also looks sloppy. It led a 350m bond issue fur the group in September. It was also a leading borrower and lender of Parma[at shares, so that in November it technically held the voting rights to over 5% of Parmalat stock. That stake had fallen to 1.5% by December 19th, the day the dairy company's black hole became public. It reported this, perhaps over-zealously, to the Italian authorities. That may have given the wrong impression, say, sources close to the bank, because the transactions were for third parties. This is awkward for a bank that managed to avoid most serious attacks on conflicts of interest thai beset the investment-banking industry following the collapse of Enron in 2001 and the bursting of the tech-stock bubble. Mr. Ackermann will need a clear head to steer the bank through the coming storms.

单选题两个都是黑尿症基因携带者的男女结婚(黑尿症属单基因常染色体隐性遗传)，他们的孩子患黑尿症的概率是______

单选题在一个细菌品系中，已知三位点的顺序可能是a-b-c也可能是a-c-b。为了确定其中之一，做了两次杂交，并选出a+b+c+重组体，当时发现杂交Ⅰ(供体a+b+c×受体abc+)和杂交Ⅱ(供体abc+×受体a+b+c)，都得到等量的+++重组体，从这些结果看，三位点的顺序可能性较大的是______ A.顺序是cab B.顺序是abc C.顺序是acb D.顺序未知，这是因为交配方式是互交，虽有等量的+++重组体，但未提供确定顺序的信息

单选题由n与n-1配子结合产生的后代是______。 A．三体 B．单体 C．缺体 D．双体

单选题 从果蝇的棒眼遗传现象，发现了位置效应的是 A、A.H.Sturtevant B、C.B.Bridges C、T.H.Morgan D、L.V.Morgan

单选题蜗牛子代螺壳旋转方向取决于母螺的基因型，该性状遗传属于

单选题 指出以下哪种动物没有同源框（homeobox） A、人； B、小鼠； C、果蝇； D、海胆

单选题对一个生物个体细胞有丝分裂进行细胞学检查，发现后期出现染色体桥，表明该生物个体可能含有______染色体。 A．臂间倒位 B．相互易位 C．臂内倒位 D．顶端缺失

单选题细菌杂交实验中，F因子和部分细菌染色体转移频率都比较高的杂交组合是( )。

单选题据测家兔体重大小是由具有相等和加性效应的一些基因决定的。在从大、小梁3品种杂交所得到的2012只F2中有8只和小亲本品种一样，还有8只和大亲本品种一样大，试问，有多少对基因在起作用?( )