Gregor Johann Mendel was the first person to explain patterns of inheritance in mathematical--and therefore very predictable--way. Before Mendel, scientists had speculated about heredity but had never tested their theories or observations. Mendel, a farm boy at heart, was fascinated by plants. He grew up on his parents' farm and was intrigued by the patterns he saw in nature. Mendel began a fateful quest to learn more about heredity by focusing on the reproductive patterns of the common pea plant.
Watch the video below to find out what Mendel learned from his early experiments.
Mendel used pea plants in his breeding experiments because they reproduce quickly, and produce a large number of offspring in each generation. Before his experiments, Mendel had noticed that pea plants produce either white or purple flowers, but never a blend of the two colors. Mendel believed that if he cross-pollinated two plants, he could then study the offspring to understand why this was so. Mendel crossed a white pea plant with a purple pea plant to see what he would get. We now know that the reproductive cells of the white flowered pea plant have two homozygous alleles, aa that are recessive -- and the purple flowered pea plant’s cells have two homozygous alleles, AA that are dominant. Mendel did not know this. He was surprised that all of his plants grew purple flowers instead of a mixture of white and purple. The results of his first experiment led Mendel to some realizations about how traits are passed on to offspring. Mendel’s law of segregation, states that the factors that cause inherited traits remain separated in the reproductive cells of organisms in order to produce separate, distinct traits in the offspring. This first experiment also demonstrated that some traits are ruled by a characteristic that is dominant, but Mendel did not arrive at this conclusion until later.
Question
What was Mendel's biggest finding in his first experiment? How might he find the lost white factor?
To understand what happened to the lost "white factor," Mendel would need to experiment with the offspring of his first generation (F1) of pea plants, to see if the white factor would come back in later generations.
