ADM-201 dump PMP dumps pdf SSCP exam materials CBAP exam sample questions

孟德尔的豌豆实验 – 译学馆
未登陆,请登陆后再发表信息
最新评论 (0)
播放视频

孟德尔的豌豆实验

How Mendel's pea plants helped us understand genetics - Hortensia Jiménez Díaz

如今 科学家们熟知你是如何遗传到父母特征的
These days scientists know how you inherit characteristics from your parents.
他们可以根据你父母和家族史的信息
They’re able to calculate probabilities of having a specific trait or getting a genetic disease
得出你获得某种遗传特征或患某种遗传病的概率
according to the information they have from the parents and the family history.
但他们是怎么办到的呢?
But how is this possible?
为了了解生物的特性
To understand how traits pass
是如何传递给下一代的
from one living being to its descendants,
我们须要回到19世纪
we need to go back in time to the 19th century
找到个叫格雷戈尔·孟德尔的人
and a man named Gregor Mendel.
孟德尔是奥地利的一位修道士
Mendel was an Austrian monk and biologist
也是热爱研究植物的生物学家
who loved to work with plants.
通过培育自己种在修道院花园中的豌豆
By breeding the pea plants he was growing in the monastery’s garden,
孟德尔发现了遗传定律
he discovered the principles that rule heredity.
在最经典的例子中
In one of most classic examples,
孟德尔将一株纯种黄粒植株
Mendel combined a purebred yellow-seeded plant
和一株纯种绿粒植株进行了杂交
with a purebred green-seeded plant,
而他只得到了黄色的种子
and he got only yellow seeds.
他把黄色称为显性性状
He called the yellow-colored trait the dominant one,
因为所有的新种子都是黄色
because it was expressed in all the new seeds.
然后他让这个新的黄色杂种植株自交
Then he let the new yellow-seeded hybrid plants self-fertilize.
在这次的子代中
And in this second generation,
他得到了黄色和绿色的种子
he got both yellow and green seeds,
这就意味着之前绿色的性状被显性黄色所掩盖
which meant the green trait had been hidden by the dominant yellow.
他把这个被隐藏的性状称为隐性性状
He called this hidden trait the recessive trait.
根据这些结果 孟德尔推断出每种性状
From those results, Mendel inferred that each trait
都取决于一对因子
depends on a pair of factors,
其中一个因子来自母本 另一个来自父本
one of them coming from the mother and the other from the father.
现在我们知道 这些因子叫作等位基因
Now we know that these factorsare called alleles
它们代表着一个基因的不同变异
and represent the different variations of a gene.
取决于每颗种子所带的等位基因种类
Depending on which type of alleleMendel found in each seed,
当两个等位基因相同时
we can have what we call a homozygous pea,
我们就称个体为为纯合子
where both alleles are identical,
当两个等位基因不同时 我们叫它杂合子
and what we call a heterozygous pea, when the two alleles are different.
这种等位基因组合被称做基因型
This combination of alleles is known as genotype
而它的结果 黄色或绿色 则被称为表现型
and its result, being yellow or green, is called phenotype.
我们可以使用棋盘法
To clearly visualize how alleles are distributed amongst descendants,
来清晰的观察等位基因在子代中如何分布
we can a diagram called the Punnett square.
只要在两个轴上都放上不同的等位基因
You place the different alleles on both axes
然后填上可能的组合
and then figure out the possible combinations.
让我们以孟德尔的豌豆为例
Let’s look at Mendel’s peas, for example.
让我们把显性黄色等位基因写成大写的“Y”
Let’s write the dominant yellow allele as an uppercase”Y”
隐性绿色等位基因写成小写的“y”
and the recessive green allele as a lowercase”y.”
大写的“Y”总是能够主宰小写的“y”
The uppercase Y always overpowers his lowercase friend,
所以想要得到绿色种子 你需要两个小写的“y ”
so the only time you get green babies is if you have lowercase Y’s.
在孟德尔第一代实验中 黄色纯合子为母本
In Mendel’s first generation, the yellow homozygous pea mom
它会给每个豌豆种子一个黄色显性等位基因
will give each pea kid a yellow-dominant allele,
而父本绿色纯合子 将提供一个绿色隐性等位基因
and the green homozygous pea dad will give a green-recessive allele.
因此所有豌豆种子都是黄色杂合子豌豆
So all the pea kids will be yellow heterozygous.
然后 在两个杂合体结合的第二代中
Then,in the second generation, where the two heterozygous kids marry,
子代会带有三种可能基因型的任何一种
their babies could have any of the three possible genotypes,
以3:1的比例表现出两种可能的性状
showing the two possible phenotypes in a three-to-one proportion.
但即使是豌豆也有很多性状
But even peas have a lot of characteristics.
举个例子 除了黄色或绿色
For example, besides being yellow or green,
豌豆还可以是圆粒或皱粒
peas may be round or wrinkled.
所以我们可能拥有如下组合:
So we could have all these possible combinations:
黄色圆粒豌豆 绿色圆粒豌豆 黄色皱粒豌豆
round yellow peas, round green peas, wrinkled yellow peas,
绿色皱粒豌豆
wrinkled green peas.
为了计算每种基因型和表现型的比例
To calculate the proportions for each genotype and phenotype,
我们同样可以使用棋盘法
we can use a Punnett square too.
当然 这计算起来稍复杂些
Of course, this will make it a little more complex.
而且 还有比豌豆更复杂的研究个体
And lots of things are more complicated than peas,
比如说 人类
like, say, people.
目前 科学家们对基因和遗传了解已经很深入了
These days, scientists know a lot more about genetics and heredity.
一些特征还有许多其它的遗传方式
And there are many other ways in which some characteristics are inherited.
但是 这一切都始于孟德尔和他的豌豆
But it all started with Mendel and his peas.

发表评论

译制信息
视频概述

现代遗传学这门学科,为人类揭示了生物的遗传规律。它告诉我们,只要实现生物之间的基因重组和转移,就有可能按照人类的需要创造出自然界从来没有的生物新品种。那么,这门新学科的创始人是谁?他又是如何发现这些遗传规律的呢?让我们一起走进19世纪的那个修道院,看一看孟德尔与他的豌豆实验吧。

听录译者

收集自网络

翻译译者

幸会,绝望先生。

审核员

审核员BZ

视频来源

https://www.youtube.com/watch?v=Mehz7tCxjSE

相关推荐