单选题 依据cDNA建立的图谱应该称为（ ） A、遗传图谱 B、序列图谱 C、转录图谱 D、物理图谱

单选题如果想知道成年人是否是XXY型，最简单的方法是______。

单选题a和b的重组值为20%，在AB/ab自交后代中，ab表型的比例为：( )。

单选题 若一个物种的染色体组成是2n=AABB=a1a1a2a2a3a3a4a4b1b1b2b3b3b4b4，则该物种是（ ）。 A、同源四倍体 B、异源四倍体 C、同源异源四倍体 D、异源八倍体

单选题用二项展开式描述多对相互独立基因经自由组合，产生后代的基因型时，二项式的指数n代表( )。

单选题As Philadelphia grew from a small town into a city in the first half of the eighteenth century, it became an increasingly important marketing center for a vast agricultural hinterland. Market days (1) the crowded city even more crowded, as farmers from within a (2) of 24 or more kilometers brought their sheep, vegetables, cider and other products for direct sale to the (3) . The High Street Market was continuously (4) throughout the period until 1736, (5) it (6) from Front Street to Third. By 1745 New Market was opened on Second Street. The next year the Callow Hill Market began (7) . Along with market days, the (8) of twice-yearly fairs persisted in Philadelphia (9) after similar trading days had been discontinued in other colonial cities. The (10) provided a means of bringing handmade goods from (11) places to would-be buyers in the city. Linens and stockings from Germantown, (12) , were popular items. Auctions were another popular (13) of trade. Because of the competition, retail (14) opposed these as well as the fairs. (15) governmental attempts to eradicate fairs and auctions were less than successful, the ordinary (16) of economic development was on the merchants'side, as increasing business specialization became the (17) of the day. Export merchants became differentiated from their importing counterparts, and specialty shops began to appear (18) general stores selling a variety of goods. One of the reasons Philadelphia's merchants prospered was because the surrounding area was undergoing tremendous economic and demographic growth. They did their business, (19) , in the capital city of the province, (20) to not only the governor and his circle, but citizens from all over the colony.

单选题 关于重复力的叙述，错误的是（ ）。　　 A、重复力是衡量同一个体某一数量性状多次度量值之间的相关程度的指标 B、重复力是一个组内相关系数 C、重复力反映了一个性状受到遗传效应和持久环境效应影响的大小 D、重复力越高说明需要度量的次数越多

单选题一外生殖器异常患者，染色质检查发现有X小体2个，Y小体1个，其核型可能为______。

单选题DNA聚合酶催化的反应( )。

单选题白眼雌蝇与红眼雄蝇杂交，后代出现白眼雌蝇的概率是( )。

单选题 遗传漂变在所有的群体中都能出现，不过（ ）。 A、群体越大，漂变就越小 B、群体越大，漂变就越大 C、群体很小时，漂变可以忽略不计 D、群体很大时，漂变的效果明显

单选题基于16SrRNA的系统发生将生物界分为( )。

单选题序列(IS)编码______。

单选题等位基因是______。

单选题有关PCR的描述下列哪项不正确?( )

单选题在烟草花叶病毒感染实验中，用A型变种的RNA与B型变种的蛋白质重建杂合病毒颗粒，再感染烟草，结果得到______子代。

单选题一个AB血型人的母亲不可能是______。

单选题睾丸女性化是( )。

单选题 断裂基因中的编码序列，称为（ ）。 A、内含子　　B、外显子　　C、转座子　　D、操纵子

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?