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  • 门德尔法

    A lion yawning, showcasing its powerful features and mane in a natural setting.

    What does it mean to be dominant?
    ::占支配地位意味着什么?

    The most powerful or influential individual in a group is sometimes called dominant. In genetics , a dominant trait means nearly the same thing. A dominant trait is the most influential trait and masks the other trait.
    ::一个群体中最强大或最有影响力的个人有时被称为占支配地位。 在遗传学中,占支配地位的特征意味着几乎相同的东西。 占支配地位的特征是最有影响力的特征并掩盖了其他特征。

    Dominance
    ::占支配地位

    Do you remember what happened when Mendel crossed purple flowered-plants and white flowered-plants? All the offspring had purple flowers . There was no blending of traits in any of Mendel's experiments . Mendel had to come up with a theory of inheritance to explain his results. He developed a theory called the law of segregation .
    ::你还记得当门德尔跨过紫花瓣和白花瓣的时候发生了什么吗?所有后代都有紫花。在门德尔的实验中,没有任何特征混合。门德尔必须提出继承理论来解释他的结果。他发展了一个称为隔离法的理论。

    The Law of Segregation
    ::隔离法

    Mendel proposed that each pea plant had two hereditary factors for each trait. There were two possibilities for each hereditary factor, such as a purple factor or white factor. One factor is dominant to the other. The other trait that is masked is called the recessive factor, meaning that when both factors are present, only the effects of the dominant factor are noticeable ( Figure ). Although you have two hereditary factors for each trait, each parent can only pass on one of these factors to the offspring. When the sex cells , or gametes ( or egg), form, the heredity factors must separate, so there is only one factor per gamete. In other words, the factors are "segregated" in each gamete. Mendel's law of segregation states that the two hereditary factors separate when gametes are formed. When occurs, the offspring receive one hereditary factor from each gamete, so the resulting offspring have two factors.
    ::门德尔建议每个豆厂对每种特性都有两个遗传因素。 每种遗传因素有两种可能性, 例如紫系数或白系数。 一个是另一个主要的。 另一个被遮盖的特性称为消沉系数, 意思是当两种因素都存在时, 只有支配因素的影响是显而易见的( 图 ) 。 虽然每个特性都有两个遗传因素, 但父母双方只能将其中一个因素传给后代。 当性别细胞, 或调子( 或蛋) 形式, 遗传因素必须分开时, 每个调子只有一个因素。 换句话说, 每个调子中存在“ 隔离” 。 门德尔的隔离法规定, 当形成游戏时, 两种遗传因素是分开的。 发生时, 后代从每个调子得到一个遗传因素, 因此, 由此产生的后代有两个因素 。

    The law of segregation predates our understanding or . Mendel developed his theories without an understanding of , or even the knowledge that DNA existed. Quite a remarkable feat!
    ::隔离法在我们的理解之前就已经存在了 曼德尔发展了他的理论 却不了解甚至不知道DNA的存在

    A close-up of pea flowers, showing purple and white petals against a blue sky.
    In peas, purple flowers are dominant to white. If one of these purple flowers is crossed with a white flower, all the offspring will have purple flowers.

    Example Cross
    ::横 示例

    This law explains what Mendel had seen in the F1 generation when a tall plant was crossed with a short plant. The two heredity factors in this case were the short and tall factors. Each individual in the F1 would have one of each factor, and as the tall factor is dominant to the short factor (the recessive factor), all the plants appeared tall.
    ::这部法律解释了曼德尔在F1一代人中看到的情况,当时高工厂与短工厂相交叉。 本案的两个遗传因素是短高因素。 F1中的每一个人都有其中的一个因素,由于高系数是短因子(停产因子)的主导因素,所有工厂都显得高。

    In describing genetic crosses, letters are used. The dominant factor is represented with a capital letter ( T for tall) while the recessive factor is represented by a lowercase letter ( t ). For the T and t factors, three combinations are possible: TT , Tt , and tt . TT plants will be tall, while plants with tt will be short. Since T is dominant to t , plants that are Tt will be tall because the dominant factor masks the recessive factor.
    ::在描述基因交叉时,使用字母。主要系数以大写字母表示(T为高),而消亡系数则以小写字母(t)表示。对于T和t因素而言,三种组合是可能的:TT、Tt和tt.T工厂将高,而TT工厂将短短。由于T为主,TT工厂将高,因为主要系数掩盖了消亡因素,因此Tt工厂将高。

    In this example, we are crossing a TT tall plant with a tt short plant. As each parent gives one factor to the F1 generation, all of the F1 generation will be Tt tall plants.
    ::在这个例子中,我们正在跨过TT高工厂和短电厂。 因为父母双方都给F1一代以一个系数,所以所有F1代都将是TT高工厂。

    When the F1 generation ( Tt ) is allowed to self-pollinate , each parent will give one factor ( T or t ) to the F2 generation . So the F2 offspring will have four possible combinations of factors: TT , Tt , tT , or tt . According to the laws of probability, 25% of the offspring would be tt , so they would appear short. And 75% would have at least one T factor and would be tall.
    ::当F1代(Tt)被允许自我污染时, 父母一方会给F2代一个因素( T 或 t ) 。 因此 F2 后代将有四种可能的因素组合: TT、 Tt、 tT 或 tt。 根据概率法则, 25% 的后代会是tt, 因而看起来很短。 75% 的后代至少有一个 T 系数, 并且会很高 。

     

     

    Summary
    ::摘要

    • One hereditary factor is dominant to the other. The dominant trait masks the recessive factor, so that when both factors are present, only the effects of the dominant factor are noticeable.
      ::一个遗传因素居于主导地位,而另一个遗传因素则居于主导地位,主要特征掩盖了隐性因素,因此,当这两个因素都存在时,只有主导因素的影响是显而易见的。
    • According to Mendel's law of segregation, there are two hereditary factors for each trait that must segregate during gamete (egg and sperm) production. As a result, offspring receive one factor from each parent, resulting in two factors for each trait in the offspring.
      ::根据Mendel的隔离法,每个特性都有两个遗传因素,在编织游戏时必须分开(卵和精子),因此,后代从父母中各得到一个系数,导致后代的每个特性有两个系数。

    Review
    ::回顾

    1. What is the difference between a dominant trait and a recessive trait?
      ::占支配地位的特征和消亡的特征之间有什么区别?
    2. Explain the law of segregation.
      ::解释隔离法。
    3. When Mendel crossed a TT tall plant with a tt short plant, what did he observe in the F1 generation? Why?
      ::当Mendel跨过TT高的植物和短短的植物时,他在F1一代人中看到了什么?为什么?
    4. If PP purple plants are crossed with pp white plants, what will be the possible combinations of factors if the F1 generation is allowed to self-pollinate?
      ::如果PP紫色植物与ppe white植物交叉,如果允许F1一代人自我污染,因素的可能组合是什么?