题干

科学兴趣小组偶然发现某植物雄株出现一突变体.为确定突变基因的显隐性及其位置,设计了杂交实验方案:利用该突变雄株与多株野生纯合雌株杂交,观察记录代中表现突变性状的雄株在全部子代雄株中所占的比率(用Q表示),以及子代中表现突变性状的雌株在全部子代雌株中所占的比率(用P表示).下列有关叙述不正确的是(    )

A:若突变基因位于Y染色体上,则Q和P值分别为1、0

B:若突变基因位于X染色体上且为显性,则Q和P值分别为0、1

C:若突变基因位于X染色体上且为隐性,则Q和P值分别为1、1

D:若突变基因位于常染色体上且为显性,则Q和P值分别为 、

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答案(点此获取答案解析)

C

同类题3

  Who hasn't enjoyed eating peanuts? Did you know that although peanuts look like nuts and taste like nuts, they aren't nuts at all? They belong to the pea family, so they are called peanuts. The peanut grows flowers above ground, but its "fruit" grows underground. It grows in more countries than most other "nuts”.
   The peanut is a native South American plant. Scientists believe that it grew wild in Brazil long ago. They think that for several thousand years the early peoples of South America made it a part of their diet. These peoples were nomads who moved on when a natural food could no longer be found in one area. Along the way they probably let fall some peanuts, which got into the ground and grew. This is believed to be the way the plant reached the place where the Incas(印加人)lived. The Incas, from about 1100 to 1532, thought highly of peanuts. The peanuts were eaten in several forms and used as sacrificial offerings(祭品)to the Incan Sun God. Later in the 16th century, European soldiers had brought peanuts to other parts of the world, including North America, Africa, Asia, Europe, and Pacific Islands.
   Although peanuts were found native in South America, they are now grown in almost every country that has warm weather. India produces the most peanuts. China's production is next, followed by the United States.
   The peanut is special in more ways than one. It can be eaten raw, boiled, roasted, or fried. Hundreds of widely different products have been made from it. Carver, an American scientist, set himself the task of discovering new uses for eating and for many other products.
  Peanuts are very highly nutritious and are also high in protein (蛋白质). Americans use about seven-tenths of their protein in the form of meat. In India, where the poor can't pay for meat or milk, peanut meal and peanut milk have been produced. These have been a great help to the poor.
  New products are continually being made from peanuts, among them peanut cheese and a powder that becomes peanut butter when water is added. The fact is that peanuts are so healthy that they were used by astronauts. The unusual nut that isn't a nut is one of nature’s most amazing gifts.