Short video spoiler history: The beginning of modern warfare

Chapter 87 Mendel's Pea Experiment

During the Hongwu period, Jinling City.

Zhu Yuanzhang, Liu Ji and others suppressed their complicated feelings and turned their attention back to the sky curtain. They found that the sky curtain only briefly introduced that the so-called characteristics were controlled by genes, but did not mention what the specific genes looked like, how to control them, how to edit them, etc.

Zhu Yuanzhang thought about it in his mind. Putting aside bacteria and viruses, there is an obvious progressive connection between hybridization technology and gene editing.

For example, hybrid wheat was created to increase wheat's original unique characteristics, such as disease resistance, drought resistance, and lodging resistance. The methods of obtaining these characteristics were through a large number of hybridization experiments, and the way they were obtained was full of randomness.

When it comes to grass carp, it was directly achieved through gene editing technology, which means that people in later generations have a deep understanding of the genes that control various characteristics of fish.

Both of them use certain means to interfere with the characteristics of wheat/fish, but one involves a bit of luck, while the other is quick, accurate, and precise.

The gap is too huge.
Hybrid wheat and rice are technologies from just a few decades ago, and although we have learned a lot from them, we still cannot fully understand them.

For example, later weapons, currency, chemical systems, materials science, etc.

[Mendel, an Austrian biologist, was revered as the father of genetics because he discovered the basic laws of genetics while serving as a priest in a monastery]

[Mendel began his exploration of the laws of heredity when he planted peas in the monastery]

Why did he choose peas as the experimental variety? It's simple, because peas are a typical self-pollinating and closed-pollinating plant.

[Simply put, pea flowers are bisexual flowers, which is what we call hermaphroditic. The function of the stamens is to produce pollen, and the function of the pistils is to receive pollen and develop into seeds. The characteristic of bisexual flowers is that they can pollinate themselves, which is self-pollination.]

[At the same time, pea flowers have completed pollination before the flowers open, which is closed pollination, so peas are purebred in the natural state]

[Secondly, the relative characteristics of peas are relatively stable and easy to distinguish, such as whether the plant has a tall or short stem, whether the seeds are yellow or green, whether the seed coat is smooth or wrinkled, etc., which makes it easier to observe and analyze the results of the experiment.]

[Finally, peas can produce many offspring at a time, so it is easy for people to collect a lot of useful data for analysis]

Nanjun in the late Han Dynasty.

"There is knowledge in every aspect of life." Pang Tong had never seen this kind of pea before, and could be said to have no knowledge of it, but since Tianmu mentioned self-pollination, there must be cross-pollination, and if there are bisexual flowers, there must be corresponding monosexual flowers, and so on.

These hidden points of knowledge are ignored as common sense.

The exploration of the world around us is a basic requirement for scientific progress. Without these observations, there would be no pea hybridization experiment, and no hybrid wheat and hybrid rice later.
"I didn't expect that even the plants used in experiments have so many details to consider." Liu Bei was very surprised. This rigorous attitude towards academic research, like that of his mentor, is truly admirable.

"It's rigorous, really rigorous." Zhuge Liang praised.

Although he did not come into contact with the sky curtain many times, each time he involved quite a few people and things. From this, Zhuge Liang also discovered that when it comes to life and work, people in later generations basically have a casual, lax, and do-it-yourself attitude, and their catchphrase is "Destroy it."

However, when it comes to scientific matters, the academic attitude of later generations has taken a 180-degree turn. From the wording of the language description to the theoretical logic, whether the experimental setup is reasonable, whether there is a control group, whether the sample is sufficient, etc., there are clear and rigorous regulations, and no carelessness is allowed.

For example, the questions and answers in the popularization of scientific knowledge mentioned in the comment section of the light bulb that was just crossed out were complained about by the young people in the comment section. From this we can see how deeply this rigorous attitude towards academic research is deeply rooted in people's hearts.

This is also what Zhuge Liang admires most.

From observing phenomena, to summarizing phenomena, proposing theories, to experimental verification.

This set of methodology was learned from the comment section. Each link in it is closely linked to each other, and the logic is seamless, which makes people convinced.

[How did Mendel conduct his pea hybridization experiment? ]

[He used artificially controlled pollination hybridization to study the inheritance of relative traits]

[For example, this piece is a tall pea, and this piece is a dwarf pea. Mendel removed the stamens of the tall pea, and then transferred the pollen of the dwarf pea to the stigma of the tall pea]

[These tall-stemmed peas produced the seeds of the first generation. He planted these seeds and found that the peas that grew all had tall stems.]

Mendel was very surprised, so he did another experiment. He removed the stamens of the dwarf peas and transferred the pollen of the tall peas to the stigma of the dwarf peas. When he planted these seeds, tall peas still grew.

[Similarly, he also conducted experiments on the skin color of peas. The results showed that when the seeds of the first generation were planted, the peas that grew were all green.]

[There are also peas with smooth and wrinkled skins. When the seeds of the first generation are planted, the skins of the peas that grow out are all smooth.]

[This is the famous first law of genetics, also known as the law of gene segregation: when an organism forms gametes, the paired genetic factors that determine the same trait will separate from each other and randomly combine and pair up. The shape expression of the next generation is determined by the combined paired genetic factors (genes)]

[For example, if two purebred pea plants are used for hybridization, if the tall stem is controlled by DD and the short stem is controlled by dd, then the genes controlling the tall stem and short stem in the offspring produced after hybridization must be Dd.]

[At this time, the seeds of the first generation grow tall after being planted, so the tall stem is the dominant gene, and vice versa. The other shapes can be deduced in the same way.] [Here, the seeds of the first generation only show tall stem peas, yellow pea seeds, smooth pea seeds, etc., because the genes that control their expression are dominant genes. As long as they contain dominant genes, they will eventually show the characteristics of dominant genes.]

During the Hongwu period, Jinling City.

"Wonderful!" Zhu Yuanzhang's eyes sparkled, as if he had crossed time and space to see the scene of the man holding a book in one hand and a cross in the other, meditating in front of the peas.

This is the smartest group of people in human history.
At that age, there was probably no gene editing technology, or the concept of gene did not exist yet, but Mendel actually figured out the inheritance patterns of dominant and recessive genetic factors (genes), and shape through simple experiments.

If we follow this first law, what characteristics will the offspring show when they are hybridized with two purebred peas, or when they are self-pollinated?

Zhu Yuanzhang picked up the pen and began to calculate on the paper. According to Tianmu, the genes that control shape appear in pairs, and during genetic pairing, they will separate from each other and pair randomly.

Then the epidermal gene of the first generation of peas is Dd. When they are crossed with purebred green peas, the offspring will definitely be DD and Dd, that is, all green. When they are crossed with purebred yellow peas, the offspring genes will be Dd and dd, with some green and some yellow.

Self-pollination also comes in green and yellow.

"It seems that I also have a talent for studying." Zhu Yuanzhang was a little complacent. This was not difficult.

[Mendel did not stop there. He continued to plant the seeds of the first generation and found that the peas of the second generation that grew had both tall and short stems.]

[However, the number of short stems is much less than that of tall stems. The ratio of tall stems to short stems is about 3:1.]

[Using a similar method, Mendel studied several other pairs of relative traits in peas, and the results were similar.]

[Mendel crossed pure yellow round peas with pure green wrinkled peas, and the purple generation peas were all yellow round.]

[This shows that yellow and round kernels are dominant traits, while green and wrinkled kernels are recessive traits]

He continued to self-pollinate the first generation, and in addition to yellow round grains and green wrinkled grains, the second generation even had green round grains and yellow wrinkled grains that were not present in the parents.

[After Mendel counted the numbers, he came up with a result of nine to three to three to one]

[If we analyze the corresponding relative properties separately, the ratio of roundness and wrinkle force for yellow and green is close to 3:1, which follows the separation law]

[That is to say, the genetic factors that control the shape of peas and the genetic factors that control the color do not interfere with each other, but new combinations have emerged between different traits]

[Therefore, Mendel explained and verified it. When the next generation produces gametes, each pair of genetic factors separates from each other, and different pairs of genetic factors can combine freely.]

[This is the second law of genetics, also known as the law of independent assortment of genes, which explains that the independent distribution of different genes is one of the important sources of biological variation in nature]

Zhu Yuanzhang was stunned for a moment. He had only calculated that after the second generation of self-pollination, there would be peas with tall and short stems and yellow and green colors. He just didn't expect that there would be such a rule to be followed.

Also, the hybridization of yellow round grains and green wrinkled grains actually produced new shapes, which is really incredible.

Looking back at his own reasoning at this time, Zhu Yuanzhang suddenly realized that because Dd was self-pollinated, four results, DD Dd Dd dd, were produced, and only dd had a dwarf stem, which explained why the visible and invisible shapes followed the ratio of 3:1.

Tang Chang'an City.

Many people were amazed after hearing this. These are the research results of the smartest people in human history. When reading these works, it feels like dealing with this group of sages. The wisdom contained in them is impressive.

Once you learn this thing, it will be useful in your life.

This is like there are many blond and blue-eyed beauties from the Western Regions in Xishi. If they marry Tang men, the children they give birth to will either be blond or black, double eyelid or single eyelid, white or yellow, and it is impossible for them to be.
"Knowledge is power!" Among so many sayings in later generations, this one is one of Li Shimin's favorites.

These one or two laws of genetics summarize phenomena that previous generations have never noticed and sort out a thread.

Following this thread, everything becomes traceable, and this is where its value is reflected.

It was from then on that people learned that various shapes were controlled by genetic factors, and they also understood some basic laws of the action of genetic factors, laying the foundation for later genetic science.

"I don't know if there is a third law." Fang Xuanling and others felt that they were not satisfied after seeing the video being replayed. This did not contradict their previous fearful mentality.

Everyone has curiosity, especially when it comes to such mysterious knowledge, which deeply reveals the secrets of life on Earth. It's something to brag about when you go out for a drink and party.

Besides, this is now popular in Chang'an City. If you go out and chat about this happily and no one can get a word in, then you are definitely inferior to others. This is commonly known as an IQ detector.

If anyone can make a convincing 123 in casual conversation, he will definitely be the most handsome guy in Kangpingfang, Dongshi.

(End of this chapter)