Genetics - Lost and Found: Crash Course History of Science #25
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Date: 2022-04-04
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Comments and reviews: 10
Aman
Gregor studied seven traits of the pea plant: seed color, seed shape, flower position, flower color, pod shape, pod color, and the stem length. There were three major steps to Mendel's experiments: -
1. First he produced a parent generation of true-breeding plants. He made these by self-fertilizing the plants until he knew they bred true to the seven traits. For example, the purple flowering plants always produced seeds that made purple flowers. He called these plants the P generation (for parent. -
2. Next, he produced a second generation of plants (F1) by breeding two different true-breeding P plants. -
3. He then produced a third generation of plants (F2) by self-pollinating two F1 generation plants that had the same traits. -
Mendel's Results -
Mendel found some incredible results from his experiments. -
F1 Generation -
Mendel found that the F1 generation all produced the same trait. Even though the two parents had different traits, the offspring always had the same trait. For example, if he bred a P plant with a purple flower with a P plant with a white flower, all of the offspring (F1) plants would have purple flowers. This is because the purple flower is the dominate trait. -
These results can be shown in a diagram called a Punnett square. The dominate gene is shown with a capital letter and the recessive gene with a lower case letter. Here the purple is the dominant gene shown with a -P- and the white is the recessive gene shown with a -w. - -
P P-
w Pw Pw-
w Pw Pw-
You can go to this page to learn more about inheritance patterns and Punnett Squares. -
F2 Generation -
In the F2 generation he found that 75% of the flowers were purple and 25% were white. Even though both parents had purple flowers, 25% of the offspring had white flowers. This turned out to be because of a recessive gene or trait was present in both parents. -
Here is the Punnett square showing that 25% of the offspring had two -w- genes causing them to have white flowers: -
P w-
P PP Pw-
w Pw ww-
Homozygous and Heterozygous -
When two of the genes are the same (like with -PP- or -ww- above) they are called homozygous. When they are different (like with -Pw-) they are called Heterozygous. -
Interesting Facts about Mendel and Inheritance-
Mendel's work was rejected by his fellow scientists while he was alive. It wasn't until later that his work was rediscovered and confirmed through further experimentation. -
Mendel was a monk and performed his experiments in the monastery garden. His experimentation largely ended when he was promoted to abbot. -
Mendel also ran experiments with honey bees, but found them much more difficult to experiment with. -
The idea that an offspring receives one unit of inheritance from each parent is the called the -theory of segregation. -
THAT TOOK AN HOUR
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Gregor studied seven traits of the pea plant: seed color, seed shape, flower position, flower color, pod shape, pod color, and the stem length. There were three major steps to Mendel's experiments: -
1. First he produced a parent generation of true-breeding plants. He made these by self-fertilizing the plants until he knew they bred true to the seven traits. For example, the purple flowering plants always produced seeds that made purple flowers. He called these plants the P generation (for parent. -
2. Next, he produced a second generation of plants (F1) by breeding two different true-breeding P plants. -
3. He then produced a third generation of plants (F2) by self-pollinating two F1 generation plants that had the same traits. -
Mendel's Results -
Mendel found some incredible results from his experiments. -
F1 Generation -
Mendel found that the F1 generation all produced the same trait. Even though the two parents had different traits, the offspring always had the same trait. For example, if he bred a P plant with a purple flower with a P plant with a white flower, all of the offspring (F1) plants would have purple flowers. This is because the purple flower is the dominate trait. -
These results can be shown in a diagram called a Punnett square. The dominate gene is shown with a capital letter and the recessive gene with a lower case letter. Here the purple is the dominant gene shown with a -P- and the white is the recessive gene shown with a -w. - -
P P-
w Pw Pw-
w Pw Pw-
You can go to this page to learn more about inheritance patterns and Punnett Squares. -
F2 Generation -
In the F2 generation he found that 75% of the flowers were purple and 25% were white. Even though both parents had purple flowers, 25% of the offspring had white flowers. This turned out to be because of a recessive gene or trait was present in both parents. -
Here is the Punnett square showing that 25% of the offspring had two -w- genes causing them to have white flowers: -
P w-
P PP Pw-
w Pw ww-
Homozygous and Heterozygous -
When two of the genes are the same (like with -PP- or -ww- above) they are called homozygous. When they are different (like with -Pw-) they are called Heterozygous. -
Interesting Facts about Mendel and Inheritance-
Mendel's work was rejected by his fellow scientists while he was alive. It wasn't until later that his work was rediscovered and confirmed through further experimentation. -
Mendel was a monk and performed his experiments in the monastery garden. His experimentation largely ended when he was promoted to abbot. -
Mendel also ran experiments with honey bees, but found them much more difficult to experiment with. -
The idea that an offspring receives one unit of inheritance from each parent is the called the -theory of segregation. -
THAT TOOK AN HOUR
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Linda
This is a revelation! Am amazed to know that Gregor Mendel studied physics yet became more interested in plants. he should be my great grandfather! I am a Physics teacher but I love to be in a garden to attend to plants, if not, be in a ranch to attend to farm animals. ) Yet his life-long work on the English peas and the result he obtained in his studies ushered in the quantitative genetics. Hot! But he maintained to be at low profile and made popular by other researches after several decades after. Grand!
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This is a revelation! Am amazed to know that Gregor Mendel studied physics yet became more interested in plants. he should be my great grandfather! I am a Physics teacher but I love to be in a garden to attend to plants, if not, be in a ranch to attend to farm animals. ) Yet his life-long work on the English peas and the result he obtained in his studies ushered in the quantitative genetics. Hot! But he maintained to be at low profile and made popular by other researches after several decades after. Grand!
reply
Aspiah
I learned more about genes. This video talks about on how organisms give traits to their descendents. Gregor Mendel give us more information and knowledge to answer the questions of our mind. While Darwin was the first person to appreciate clearly that evolution depends on the existence of heritable variability within a species to generate the differences between ancestral and descendent populations. Every child inherits genes from both of their biological parents. What a great information!
reply
I learned more about genes. This video talks about on how organisms give traits to their descendents. Gregor Mendel give us more information and knowledge to answer the questions of our mind. While Darwin was the first person to appreciate clearly that evolution depends on the existence of heritable variability within a species to generate the differences between ancestral and descendent populations. Every child inherits genes from both of their biological parents. What a great information!
reply
Ercan
Well, that 4 rediscoverers look like they are guided to mendel by their curiosity but it is the truth that they give mendel the share of success instead of selfishly claim it for themselves. Those guys have at least basic level of a moral code unlike Einstein or thomas edison who were only thinking about taking the fame and glory for themselves instead of sharing it with their predecessors or rivals.
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Well, that 4 rediscoverers look like they are guided to mendel by their curiosity but it is the truth that they give mendel the share of success instead of selfishly claim it for themselves. Those guys have at least basic level of a moral code unlike Einstein or thomas edison who were only thinking about taking the fame and glory for themselves instead of sharing it with their predecessors or rivals.
reply
Mac
And now Mendelian genetics is pretty irrelevant when it comes to most traits that scientists what to study like height, cognitive ability, schizophrenia etc.
After the human genome was sequenced scientists discovered that most complex traits are highly highly polygenic to the degree most scientists are advocating for an omnigenetic model.
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And now Mendelian genetics is pretty irrelevant when it comes to most traits that scientists what to study like height, cognitive ability, schizophrenia etc.
After the human genome was sequenced scientists discovered that most complex traits are highly highly polygenic to the degree most scientists are advocating for an omnigenetic model.
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Ivan
Green, you create an anachronism when you use the word genes in the writing of the 3 Mendelian Laws, as the term did not exist at the time and, obviously, could not have been used by Mendel in his laws as one might understand from the video.
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Green, you create an anachronism when you use the word genes in the writing of the 3 Mendelian Laws, as the term did not exist at the time and, obviously, could not have been used by Mendel in his laws as one might understand from the video.
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VRBG
11: 02 She's the most important woman in the history of genetics, and yet i had never heard of her before, she WON an actual unshared Nobel Prize. AND I HAD NEVER HEARD OF HER IN SCHOOL! how insane is that?
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11: 02 She's the most important woman in the history of genetics, and yet i had never heard of her before, she WON an actual unshared Nobel Prize. AND I HAD NEVER HEARD OF HER IN SCHOOL! how insane is that?
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Tfin
-The only woman to have received. -
Wow
-. an unshared nobel prize. -
Oh. With so many prizes going to multiple people, that's a bit less.
-. in that category. -
Pfff.
reply
-The only woman to have received. -
Wow
-. an unshared nobel prize. -
Oh. With so many prizes going to multiple people, that's a bit less.
-. in that category. -
Pfff.
reply
Dhairyashil
Mendel was student of the famous physicist and mathematician Doppler. The quantitative work in biology by Mendel had its inspiration/origin in that past training.
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Mendel was student of the famous physicist and mathematician Doppler. The quantitative work in biology by Mendel had its inspiration/origin in that past training.
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Julietta
Didn't Mendel also groom his data and smooth out errors and inconsistencies? I was under the impression that his published data wasn't entirely honest
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Didn't Mendel also groom his data and smooth out errors and inconsistencies? I was under the impression that his published data wasn't entirely honest
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