单选题睾丸女性化是( )。

单选题豌豆中，高茎(T)对矮茎(t)为显性，黄子叶(Y)对绿子叶(y)为显性，假定这两个位点的遗传符合孟德尔第二定律，若把真实遗传的高茎黄子叶个体与矮茎绿子叶个体进行杂交，F 2 代中矮茎黄子叶的概率是______

单选题下面是关于红色脉孢霉(Neurospora crassa)遗传分析的陈述，请选择最佳选项。______ A．由于红色脉孢霉的子囊狭窄，减数分裂后的4个同源染色体在子囊中顺序排列 B．作为细菌遗传分析的模式物种，红色脉孢霉可以利用着丝粒作图法进行基因定位 C．在红色脉孢霉中，减数分裂第二次分裂(MⅡ)的比例可用于计算某基因位点与着丝粒的重组率 D．由于红色脉孢霉的子囊狭窄，减数分裂后的4个染色单体在子囊中顺序排列

单选题转座作用前后DNA的含量变化是： ____ 。

单选题The inheritance pattern of dimple is dominant. A man with dimples who was married by a woman without dimples gave birth to 8 children, and interestingly, all the eight children have dimples in their faces. The most possible genotype of this man is______． A．Aa B．AA C．aa D．unable to be inferred

单选题细菌中，同源重组发生在一些热点周围，这和 ____ 在chi位点上的单链内切酶活性有关。

单选题George Williams, one of Scottsdale's last remaining cowboys, has been raising horses and cattle on his 120 acres for 20 years. The cattle go to the slaughterhouse, the horses to rodeos. But Mr. Williams is stomping mad. His problems began last year when dishonest neighbours started to steal his cattle. Then other neighbours, most of them newcomers, took offence at his horses roaming on their properties. Such grumbles are common in Arizona. The most recent Department of Agriculture census shows that 1 213 of Arizona's 8 507 farms closed down between 1997 and 2002. Many cattlemen are moving out to remoter parts of the state. Doc Lane is an executive at the Arizona Cattlemen's Association, a trade group. He says Arizona's larger ranch owners are making decent profits from selling. It is the smaller players who are the victims of rising land values, higher mortgages and stiffer city council rules. What happens all too often is that people move in next to a farm because they think the land pretty. But soon they start complaining to the council. In Mr. Williams's case it was the horses that annoyed them. Other newcomers don't like the noise, the pesticides and the smell of manure. Locals worry about the precious, dwindling cowboy culture. Arizona's tourism boards like to promote a steady interest in all things about cowboy and western. Last year more British and German tourists came than usual, and many of them were looking precisely for that. Arizona's Dude Ranch Association fills its $ 350-a-night luxury ranches most of the year; roughly a third of the guests are European. Many of the ranchers themselves see all this tourism as a cheeky attempt to commercialise a real and vanishing culture. In Prescott, estate agents promote "American Ranch-style" homes with posters of horse riders. On the other side of the street is Whiskey Row, a famous strip of historic cowboy bars. But in Matt's Saloon on Saturday night, real cattlemen could not be found. Farm folk like Mr. Knox and Mr. Williams are weighing up their options. Many will migrate to remoter places where land is cheaper and not crowded with city people. Younger ones take on side-jobs as contractors and are cattle-hands part-time. Older cowboys aren't sure what to do.

单选题具有一对杂合基因的个体连续自交______代，才能使约97%的个体纯合。 A．3 B．5 C．6 D．7

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

单选题假设某种二倍体植物A的细胞质在遗传上不同于植物B，为了研究核一质关系，想获得一种植株，这种植株具有A的细胞质，而细胞核主要是B的基因组，应该怎么做?

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?( )

单选题The history of responses to the work of the artist Sandro Botticelli (1444 ～ 1510) suggests that widespread appreciation by critics is a relatively recent phenomenon. Writing in 1550, Vasari expressed an unease with Botticelli's work, admitting that the artist fitted awkwardly into his evolutionary scheme of the history of art. Over the next two centuries, academic art historians defamed Botticelli in favor of his fellows Florentine, Michelangelo. Even when anti-academic art historians of the early nineteenth century rejected many of the standards of evaluation adopted by their predecessors, Botticelli's work remained outside of accepted taste, pleasing neither amateur observers nor connoisseurs. (Many of his best paintings, however, remained hidden away in obscure churches and private homes. ) The primary reason for Botticelli's unpopularity is not difficult to understand: most observers, up until the midnineteenth century, did not consider him to be noteworthy, because his work, for the most part, did not seem to these observers to exhibit the traditional characteristics of fifteenth-century Florentine art. For example, Botticelli rarely employed the technique of strict perspective and, unlike Michelangelo, never used chiaroscuro. Another reason for Botticelli's unpopularity may have been that his attitude toward the style of classical art was very different from that of his contemporaries. Although he was thoroughly exposed to classical art, he showed little interest in borrowing from the classical style. Indeed, it is paradoxical that a painter of large-scale classical subjects adopted a style that was only slightly similar to that of classical art. In any case, when viewers began to examine more closely the relationship of Botticelli's work to the tradition of fifteenth-century Florentine art, his 'reputation began to grow. Analyses and assessments of Botticelli made between 1850 and 1870 by the artists of the Pre Raphaelite movement, as well as by the writer Pater (although he, unfortunately, based his assessment on an incorrect analysis of Botticelli's personality), inspired a new appreciation of Botticelli throughout the English-speaking world. Yet Botticelli's work, especially the Sistine frescoes, did not generate worldwide attention until it was finally subjected to a comprehensive and scrupulous analysis by Home in 1908. Home rightly demonstrated that the frescoes shared important features with paintings by other fifteenth-century Florentines features such as skillful representation of anatomical proportions, and of the human figure in motion. However, Home argued that Botticelli did not treat these qualities as ends in themselves--rather, that he emphasized clear depletion of a story, a unique achievement and one that made the traditional Florentine qualities less central. Because of Home's emphasis crucial to any study of art, the twentieth century has come to appreciate Bottieelli's achievements.