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Me, Myself and Us Name ___________________
Gregor Mendel does Science with Peas Period ___________
Crosses 1->4 Student #_____
to crosses 1-4
. . . . . In the early 1800's no one really knew why most plants and animals produced offspring that were totally unlike their parents. They did know, however, that some characteristics nearly always breed true, like blue eyed parents always had blue eyed children, Labrador retrievers always had Labrador retriever pups, Macintosh apples offspring looked like Macintosh apples, and Arabian horses had foals that looked just like them. They also knew you could breed a horse to a donkey the offspring would be a hybrid of the two animals, namely a mule, and it was sterile. However, NO ONE knew what caused all this to happen!
Then young Johann Mendel came onto the scene (He changed his name to Gregor when he became a monk). Mendel was from a small farm, located in what is now part of the Czech Republic. In lower school Gregor received lots of agricultural training as they had a progressive farming community. As he grew older Mendel became sickly, but overcame this obstacle and financial hardships to excel in high school and in the Olmutz Philosophical Institute. Throughout all these early years Gregor always loved nature. So he wanted to be a naturalist, which is a person who enjoys and studies the diversity of life nature provides.
In those days there was an old European tradition - if you were a son of a rich family, you'd inherit the family's wealth, the second son often went into the church, and the third became an adventurer to seek his own wealth. But Gregor's family wasn't rich, so hanging around to inherit wasn't going to be a real good deal. Instead, being a very spiritual fellow, he chose the church. Mendel became an Augustinian Monk at the age of 20. Now this was a pretty good deal all around. Churches were strongholds of education. In fact, in the centuries past, many of Europe's royal families and scientists were originally trained by the church. Well, Gregor found himself in the best of both worlds, he lived in a spiritual environment and was allowed to work with nature too! Well, after three years of theology training, Gregor was sent to be a teacher, but failed the exam! So the head monk sent him to study at the University of Vienna where he learned about math and botany (plants). One of his professors, Doppler, trained him to use math to document scientific phenomena. (just like you are being taught to do!) The other, Professor Unger, awakened an interest in Mendel to study inheritance in plants.
Mendel ended up teaching in Austria at the Brunn Modern School where his interest in plants and math blossomed!! (No Joke!) The Augustinian monastery in Brno where he lived from (1843&emdash;68) fully supported his studies, and in 1857 Mendel began his famous study of inheritance in peas.
Mendel probably studied peas because they were available in many varieties. For example peas bloomed in either purple of white, there were peas that were either smooth or wrinkled, and they were colored either yellow or green.
Gregor kept strict track of the results of his many pea cross pollination experiments. In fact, his data, although not perfect by far, were far better than any of the previous genetics researchers. This was really important! That's because the results of his careful experiments revealed that the genetic traits he studied were passed down through the generations from parent plants.
Mendel's finding revolutionized the entire scientific thoughts about genetics. However, they weren't publicized until three independent researchers independently achieved the same conclusions fifty years later and gave proper credit to Mendel! Whew!
So ok, here we have this nature loving Monk running amok in the Brno monastery Pea patch!! Mischief was sure to happen, thought the friars in charge. But Mendel kept his head down in his work. (Although there is a rumor he started the child's rhyme about eating peas with honey during this time.... but then again, what the heck, you'd grow a little stir crazy too if you spent all of your time fertilizing and counting peas! (He called them his "Children"!)
Well, what did our erstwhile monk do all this time, from 1857-1866, anyways? As we mentioned before Mendel noticed that peas have definite characteristics, or traits. The seven he studied were:
Trait
Form 1
Form 2
Tallness
Tall
Short
Color
Yellow
Green
Pod shape
Inflated
Wrinkled
Pod color
Green
Yellow
Flower color
Purple
White
Flower position
Along stem
At tip of stems
Seed shape
Round
Wrinkled
What Mendel actually did was cross pollinate pea plants with the different traits. For example he cross pollinated a tall pea flower with a short pea's pollen, round seed plants with wrinkled seed pollen, etc, then covered the flowers so they wouldn't be further pollinated. Then the fantastic friar observed the plants and finally collected and counted the first generation's offspring seeds later. He analyzed the results during the winter.
The next season Gregor went out and did the same thing. But this time he used the seeds and pollen of the offspring plants from the previous year. During the year Mendel observed the plants and finally collected and counted the second generation's offspring seeds later. He analyzed the results during the winter.
Gregor repeated his tests during the years, after about six years of analyzing the new data he realized that the offspring were produced in specific proportions.... this startling relevation led him to create his now famous Law, which has two parts or principles!! .. .. . .Here they are.
Mendel's law (1865)
Principle of Segregation
1. Members of a pair of homologous (like) chromosomes separate during meiosis and are distributed to different gametes (sperm and egg cells).
Principle of Independent Assortment
2. Each member of a pair of homologous (like) chromosomes segregates during meiosis independently of the members of other pairs. Alleles carried on different chromosomes are distributed randomly to the gametes (sperm and egg cells).
Mendel also established that one form of each trait would often dominate, or mask, the other form. (Sometimes, though they would blend together, but that's a different story.)
I'd like you to learn some more about his Genetics experiments, so lead and read on......
Mendelevian Genetics - Lets use what we know to solve some genetics crosses!!
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