Genetics: Mendel's Theory Flashcards
Test review
What were the early beliefs about genetics? (Blend theory)
Traits from parents blended in their children. Was disregarded due to being unable to explain appearing and disappearing traits generationally.
Who was Gregor Mendel (1822-1884)?
An Austrian monk who bred pea plants. His work was done in 18th century, but was only recognized in the 20th. The father of Genetics.
Why did Mendel use pea plants?
1: They are easy to grow and maintain
2: They are readily available
3: They produce large offspring numbers in short time
4: Peas are perfect plants (Have male and female parts), therefore are able to self and cross pollinate
5: Different pea plants show easily distinguishable traits
What was the second part of Mendel’s experiment?
Mendel wanted to cross-pollinate pure plants of one trait with another. These were the P1 generations. After he crossed the P1 plants and grew their seeds, he found all of them to be of one (dominant) trait. These plants were the F1 generation. They were hybrids since they were crossed between 2 pure parents, but only showed one of the original traits.
What was the first part of Mendel’s experiment?
He realized the plants’ traits came in one of 2 forms and then studied multiple pairs to contrast them. Discovered some plants bred pure for certain traits after self pollinating for several generations, always producing same trait offspring. Mendel considered these plants pure for their respective traits. (True breeding)
What is Mendel’s Law/Principle of Segregation?
1: Distinct units or factors determine heredity characteristics
2: For each characteristic, an individual carries two factors: one inherited from each parent
3: The two factors of each pair segregate from each other and end up in separate gametes
What was the last part of Mendel’s experiment?
Mendel wished to check if the other (recessive) trait was lost in the F1 generation, and allowed them to self pollinate. When their seeds were planted and grown ~25% of the plants were one (recessive) trait and ~75% of the plants were the other (dominant) trait. These were the F2 generation. Other tests on other traits yielded the same results.
What is Mendel’s Law/Principle of Dominance?
States that each trait in an individual is controlled by factor (gene) pairs. One factor produces one trait, whilst the other produces the other. One factor dominates the other, masking it.
“When there are two forms for a particular trait, the dominant form will prevent or mask the expression of the recessive form.”
