Mendel's Pea Cross Breeding Experiment孟德尔的豌豆杂交育种实验

Mendel's Pea Cross Breeding Experiment

孟德尔的豌豆杂交育种实验

Mendel was born in Silesia in the Austrian Empire, his parents were horticulturalists, which gave Mendel more opportunities to contact plants during daily life. Mendel's most famous experiment was the "Mendelian pea hybridization experiment," which led to theories that underpin today's genetics. He is the  founder of modern genetics, so he is called the "father of modern genetics".

孟德尔出生于奥地利帝国的西里西亚，他的父母都是园艺家，而这给了孟德尔很多能跟植物经常打交道的机会。孟德尔最为著名的实验是 “孟德尔豌豆杂交实验”，该理论支撑并且催化了现代基因学的理念。因此孟德尔被称为现代基因学的奠基人，并被称呼为 “现代遗传学之父”。

Mendelian chose to study the inheritance of Pisum sativum in the "Mendelian Cross Experiment". He chose peas because peas are strictly self-pollinating, closed-flowering plants. So the offspring of peas are purebred, which makes the results of hybrid experiments reliable. Also, these traits in peas were stably passed onto offspring. Crosses between pea varieties with these easily distinguishable and stable traits make the experimental results easier to observe and analyze.

孟德尔选择研究豌豆的遗传是因为豌豆是一种完全自我授粉的闭花植物。因此豌豆的后代都是纯种的，这使杂交育种实验的结果更加可信。此外，豌豆的特性会稳定地传给后代。拥有着这些易于区分和稳定性的豌豆会使我们更容易分析和观察实验结果。

During the experiment, He used purebred tall and dwarf peas as parents and cross-pollinated their different plants. It was found that the first-generation plants (indicated by F1) obtained from their crosses showed tall stems whether they used tall stems as the female parent, short stems as the male parent, or vice versa. Therefore, as far as this pair of relative traits is concerned, the trait of F1 plants can only show the trait of one parent—high stem, while the trait of the other parent—dwarf stem is not shown in F1.

在实验过程中，孟德尔选择了纯种高豌豆和矮豌豆来作为亲本，并进行了异花授粉。结果发现，第一代花（图中表示为F1），无论以高茎为母本，以矮茎为父本，或者恰恰相反，均表现出高茎。因此，F1植株的特性只能表现出一个亲本的特性 -- 高茎，但是另一个亲本的特性 -- 矮茎，并没有在F1植株里体现出来。

In the above experiment, since only one of the relative traits（the dominant trait） is shown in the hybrid F1, then, does the other trait in the relative trait ( the recessive trait ) disappear? With such doubts, Mendel continued his hybridization experiments. Mendel self-pollinated F1 tall peas, and then sowed the resulting F2 pea seeds the following year to obtain hybrid F2 pea plants, resulting in two types: one is tall peas ( Dominant trait), one is short-stemmed pea (recessive trait), that is: two different manifestations of a pair of opposing traits - both tall and short-stemmed traits are expressed. Mendel's doubts were lifted, and he called this phenomenon “the phenomenon of separation”.

在以上实验里，由于杂交出来的F1植株只显示了一个特性（称为显性特性），这就代表着另一个特性（隐性特性）就消失了吗？带着这样的疑惑，孟德尔继续了他的育种实验。在实验里，孟德尔手动给F1高茎植株自花授粉，并在次年播种了所得的第二代（F2）的豌豆种子，目的是为了得到F2豌豆的植株。F2植株产生了两种类型：一个是高茎豌豆(显性特性），另一个是短茎豌豆（隐性特性），即：一对对立特性的两种不同表现方式 -- 高茎和短茎的特性都体现出来了。孟德尔的疑惑被打消了，并管这个现象叫做 “分离现象”。

In F2, the relative traits of the hybrid parents—dominant traits and recessive traits—are displayed again, which is “the phenomenon of trait segregation”. It can be seen that the recessive traits did not disappear in F1, but were temporarily covered and could not be expressed.

在F2植株里，（F1）杂种亲本的相关特性 -- 显性和隐性特性 -- 又一次的被体现了出来，被称为 “特性分离现象”。可以看到的是F1植株里的隐性特性并没有消失，而只是被暂时的覆盖住了，因此无法体现出来。

In 1866, Mendel published his thesis "Experiments on Plant Hybridization". In it, he proposed that inheritance is the result of each parent passing on a factor for each trait. If the factor is dominant, it will be expressed in offspring. If the factor is recessive, it will not appear, but will continue to be passed on to the next generation. Each factor acts independently of the others, and they do not mix.

在1866年，孟德尔发布了他的论文 《植物杂交育种实验》。在论文里，他提出了遗传就是每个亲本为每个特性传递一个因素的结果，并且这个特性会在后代里展现出来。如果这个因素是隐性的，这个因素并不会消失，只是会继续遗传给下一代。每个因素都是独立的，不会混合。

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