Blending would cause traits to be lost or modified in later generations, and Mendel’s experiments demonstrated that recessive traits remained intact from generation to generation, although they may not be evident due to the presence of a dominant trait in the individual. The results of single-trait crosses clearly indicated that the genetic material was not being blended. His results clearly indicated that in the first generation, one of the two variants of the trait dominated the other, or recessive, trait. Three basic principles of inheritance were established, or supported, by Mendel’s monohybrid crosses. The law of hybrids uniformity in the first generation (dominance law) Statistical approach raised the validity of his works tremendously.ġ) dominant or recessive trait and corresponding gene ģ) the interaction of genes and the nature of this interaction Mendel repeated his experiment many times so as to increase the number of offspring. Plant height 100% tall 787 tall: 277 dwarf 2.84:1Įach of the crosses yielded approximately a 3:1 ratio in the second generation. Trait F 1 Generation F 2 Generation Ratio When the round-seed-producing plants of the first generation were crossed with one another, the plants of the second generation (F 2 generation) demonstrated a yield of 3/4 round-seed-producing plants and 1/4 wrinkled-seed-producing plants. If they were, there should be plants of intermediate seed. The presence of all round seed plants in the first generation (F 1 generation) indicated that the traits were not blending together. When plants producing round seeds and plants producing wrinkled seeds are crossed, they yield plants that produce round seeds. These were the round and wrinkled variants. In his first experiment, he crossed two pea plants that possessed true-breeding variants of seed shape. Mendel examined the quantitative laws of inheritance. FigureThe Seven Traits that Mendel Studied in Pisum Sativum
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